You will have to remove the bridge studs or tailpiece studs (there are simple tools for this) and drill through to the cavity. Thread the new ground wire in so it just pokes out of the stud hole. It will then make a good contact to the stud as you press that back in. No other way to do it neatly. This ground wire should be soldered to the ground loop that goes around the pots in the cavity. Fixed.
TS, actual opinions.
Epi - Overpriced, get a better deal on an Agile
Dean - Expensive firewood
Jackson - Nice but more limited in styles than a LP type
Ibby - Many of the good points of a LP but with less control over sound than an Agile.

Webwarmiller has found you some great options if you can jump on those offers.
EMG active pups - Loud, sterile but great through a good valve amp
SD 59/Custom will give warmer and more versatile sounds
P-rails Best combination for humbucker, P90 and SC tones so very versatile
Which Vox do you have? An AC30 is going to be a lot louder than one of their SS or hybrid models.
The 6505 will get you great driven sounds but not anywhere near the cleans you need. For those you are looking at Fender, Hiwatt and Vox, which, if you need a lot of power, are going a good bit above your budget. So, back to basics of amp buying and get the cleans right first. One amp that I have been impressed with on the clean side is the Kustom Defender 50w. That would be about within your pocket so would be worth checking out.
£250 will get you a Vintage V100 (even a Lemon Drop) but it won't sound great through that amp. Still, a good place to start and when you upgrade the amp you'll enjoy it all over again.
Yamaha tried a lot of shapes before they settled on the SG type we know as a sort of double cut Les Paul Custom. Most Yammys are well put together.
A very versatile guitar in your price range is the Cort Z44. Also the finish is excellent and is far more comfortable to play than the average Les Paul shape. Well worth trying.
Check your action - string height. It means you are bending the string too far to reach the frets causing the pitch to be too high. Action at 12th fret should be around 1.5mm +- a bit to taste.
Sustain is the guitar's natural resonance when played unplugged.
Controlled feedback is what players get on stage which causes a note to keep sounding through the amp. The moving air from the speakers causes the guitar to vibrate the strings, thus creating a feedback loop. Rest the headstock of the guitar on the speaker cab and you cut out the bit where the sound travels through the air.

Strat style guitars typically have a problem getting controlled feedback unless you use a big amp. The solid electric guitar was actually designed to prevent feedback through the resonant body that archtops had.

So pickups have almost nothing to do with it.
I chose the roland because its not a modeling amp. Clean sounds are pretty good for a £75 amp but with your bit extra money I'd probably suggest the 20x
First you narrow it down to what sort of pickup & sound you want. Then you compare prices around what you can afford. Then you look at the makers' sites and check out the sound samples, noting what guitar they were used in and what amp they were played through. When you have it down to maximum half a dozen, you could ask opinions on here although that is liable to just produce everyone's favourites.
Add Cort to the list. You can check them all at Thomann in Germany and I'm pretty sure they will deliver to you for a lot less than $100.
scroll down and you'll see pics of the 'debbie' LP types. These are the upmarket version of mine and are excellent. Great neck, Ebony board, 1/2 inch of maple top. Tuners are Wilkinson. If I had some dosh that cherry burst would be mine.
Arctic Monkeys = Hiwatt DR103 But it needs help for the high gain stuff. Should find a mint used one at a fair price (maybe $1500) Early eighties and before are considered among the best amps ever made.
Hiwatt HG100 has the same cleans through a circuit board rather than p to p wiring, but it has a 2 stage gain channel as well. These, as all Hiwatts, work best with the Fane loaded Hiwatt cabs but are alright with Celestions. Good news is that the whole 1/2 stack would be well within your budget.
Yes but........ The XD has a lot of built-in effects which would either not work nicely alongside pedals or would need quite a bit of work to get the best out of both.
My experience goes against what a lot of you are saying. My Ellis LP came with overwound Wilkinsons. (14k & 13.2k) and they kind of hit a middle ground, being good for overdriven sounds but very bright in the cleans. When I got a set of hand made Skatterbranes (7.8kA5 neck & 7.8k A2 bridge) I was expecting a big loss of output but better cleans. So I was a bit shocked that the actual playing volume was much the same but the articulation and sensitivity to touch was dramatically improved. To my ears they also cope well with heavy drive and retain a lot of definition.
If I wanted hot passives I'd probably go with Rock Monkey SOBs (26k neodymium) but its unlikely while I have EMGs in my Cort.
When you say, 'many years' this could pose a problem. When Trev Wilkinson got into Vintage guitars they switched entirely to his hardware and the quality went up immediately. IF its new enough to be a Wilkinson one, then the pickups will be the standard ones which are medium output and a bit bright. That may be no bad thing on a VS6.
Obviously a good setup will be wanted but keep the pups in until you find the faults. If you decide to change them later, any PAF style with A5 magnets would be the right direction for an SG.
Take a look at Axetech and Axesrus for replacement tuners, though the Wilkinsons are pretty good quality.
Quote by GodlessHeathen

Really nice amp for British cleans, blues etc.
Look at the Irongear pickups range. (yes they ship all over) Very good value pups with several that will suit your needs.
Put a Hot Rails or similar in the middle and a fairly hot h/b in the bridge. Irongear have their specialist Metal pups (Sledgehammer & Hammerhead) both around 15k and their Jailhouse Rails is a 13k single coil size humbucker. At their prices, the pair will cost less than one SD or DiMarzio humbucker and you will keep better balance between all 3 pups.
€500 will get you a Kustom Defender 50w combo (probably with change) from Thomann. Its only a 1x12 but for another €100 or less you could add a second cab and have versatility when you can afford it. As for its sound range, if you ever listen to the samples from JHS of their Vintage guitars, they are all done on Kustom amps. Certainly will take you from blues to hard rock, though a pedal might be best for metal.

btw, Dave. Even in NI you pay a little bit of VAT. That's taxes.
I'd seriously look at Norlin era Gibsons of the less popular models. Les Paul Specials and Juniors, SG DeLuxe if you are lucky. Even Melody Makers will gain in value. Right now the market is pretty low so its as good a time to invest as any.
Beware some of the 70s Japanese knock-offs. Their bubble is burst unless you find something from the Fujigen factory after they switched to set neck construction. Japanese Orville's are good and the 80s Burnys will keep rising. All these are pretty rare so you won't often find them on Ebay-UK. And everyone looks there so you'd likely get a better deal elsewhere.
For alternative and punk rock you might try a Hiwatt Maxwatt 100 combo. Should be around the right price and you get a good little amp for the money. 2 channel non-modeling and can drive an external cab if the need arises. Otherwise its nicely portable without lifting gear. And 100w SS will more than match even the heaviest drummer.
All nice guitars. All different scale lengths so two of them will take extra getting used to as well as the change to 7 string playing.
As for calming down for RHCP, all these guitars have volume knobs and I know that EMGs do clean up remarkably well below about 7.
You position the unit so the tuning knob sticks out at 90deg to the edge of the headstock. While you are changing them, do remember to drop a bit of graphite (pencil lead shavings) into the nut slots. It helps the string slip through instead of sticking which is 90% of Strat tuning problems.
1, 2nd link is wrong
That actually looks like a reasonable deal for a starter pack.
2, What Strat have you been borrowing? That Affinity is not among the better respected Squiers and I can see nothing there that warrants the extra price other than the Fender name.
You will get close with BKP War Pigs. You might get even closer with Irongear Platinum 90s which are humbucker sized. I can get almost spot on with my Skatterbranes but they are a bit pricey.
1) how do you communicate with other guitarists? (is there any slang/jargon that you particularly use that the average person would not understand? what methods of communication do you use? [verbal, computer/internet, etc.]) does your word choice vary from normal conversation with other guitarists?

Yes it is a little different when you know the other person will understand any jargon and its often easier to use it to get an idea across.

2) list every type of music you know which involves a guitar (you can list genres and sub-genres [ex: rock, hard rock, soft rock, etc]).

jazz, blues, folk, country, R&R, pop, rock, 17 types of metal, classical, latin, calypso, funk, ska, punk, acid, space, the list is endless.

3) list all the techniques you know (whether you can perform them or not).

You mean like sweep picking, alternate picking, shredding, tapping, regular picking, strumming, arpeggio, hammer on, pull-offs, finger picking, pinch-harmonics, bowing, and hammering (striking the string with an object). Oh and slide, plus the various tricks with a whammy.

4) when communicating with other guitarists, what do you typically talk about with them?

Sex and drugs and rock 'n' roll. Slagging off show-offs, booze. Sometimes even guitars.
A close call between my two favourites.
1, Pack Leader Walnut
2, '61 LP/SG Custom
I owned them both.

Less perfect players:
'59 LP burst Nice but not quite
'54 LP Goldtop Horrible but amazing sound.
Or you can edit out the latency in Audacity as you add each track.
Scroll down to the Series 1 offerings. A mate of mine has a PRS and an Ellis S1 Hollow body. He says the Ellis feels and sounds way better. His has JB/59 pickups from Seymour Duncan in, for which he paid a litttle extra. Tim will quote you for what you want and give you the best shipping he can find.
Roland 15x for travelling around but Microcube or whatever the new one is, for battery type use.
A gigging amp for $300. Time to compromise. You can't get more cash fast and you can't gig with a practice power amp. Go SS.
Hiwatt Maxwatt 100 combo. It will do what you want in cleans and is twin channel. Its small enough to haul around and loud enough for any gig (mic'd for huge ones). Downside is it is not a valve amp so the sound is a little bit sterile. But its one of the better sounding SS amps and its not a modeler so tends to take pedals pretty well.
Basswood body. You can't compare natural resonance with a Mahogany or Alder body. Basswood is not intended to be as resonant so less 'body sound' gets through. Get your treble side of the pickups right then back off the bass side until you get the best balance.
If you are going for new pups, something with adjustable poles will suit better than the cool looking black tops.
And the speakers need to be minimum 100w rated each. I'd go for Fane 200w ones but that's me.
There is no better or worse about MFX vs stomp boxes. Their uses tend to be a bit different. If you are playing originals and you have exact sounds you like from any box, you can't beat individual on a pedal board.
But. If you play in a covers/pub type band and are prepared to W O R K at getting the settings for each song in the set, you can get good sounds and instant switching from one to another. The first time you fall over on stage, trying to do the Mad Guitarists Tap Dance, you'll go and get a MFX for practical gigging. Keep the board too, for those simple sounds that you set and forget.
Hahaha not a dealer but a drug squad copper. I was only going to ask a hot dog seller in Birmingham for directions and he bolted with a bag in his hand. My mate went back later and got the story. (but not the drugs)
Kustom Defender 50. 1 x 12 50w valve combo so its small enough for portability, loud enough for gigs and its only a tad over your budget. Those 50 watts will give you the headroom you need for the clean stuff. This is better than trying to push a 15 or 20 wattt amp and lose any kind of clean.
Vintage are probably the biggest selling brand in UK. No-one's heard of them? Dolphin, GAK and Thomann are stocking them BUT there are serious QC issues so never buy a Vintage online. Get a good one and they are very good for the money. Retailers are about 30-40% below JHS list price. I have a set of their overwound pups in my Alder Yamaha and it sounds like an ice-pick scraped over glass.