I have an Ibanez GRX40 wich I like very much, so I'd like to mod it to make it better by installing some new pickups(3 single coils) and some new locking tuners because my guitar gets out of tune fast when using the tremelo, I also might want to change the nut.
But if I mod it I will put stuff in it that's more expensive than the guitar self. so, my question is: shall I mod my guitar or its it better to buy a new guitar(I want to buy a fender than)

A hero of war, Yeah that's what I'll be

it will be less of a hassle to just buy a new guitar but it might not be exactly what you want i play ibanez and now find fender necks very uncomfortable because im used to a wizard 2 so i would definitely play it before you buy it if you go that route plus in the guitar world ive found feally in the end you get what you pay for hope this was helpful in some why
I would get a new guitar. I've had horrible experiences with the Ibanez Gio series. Search Musicians Friend or the Ibanez site and try to find a similar, higher end Ibanez if you like the one you've got. Although, modifications to the tuners and pickups may still be required. Just try (extensively) before you buy.
Then there's this band called Slice The Cake...

Bunch of faggots putting random riffs together and calling it "progressive" deathcore.
Stupid name.
Probably picked "for teh lulz"

Mod in UG's Official Gain Whores
Well, since everyone agrees that buying a new guitar is the road to go, can you tell us a few things about what you want? Ill list a few questions, you try to answer them as clearly as you can.

1: Price range?

2:Playing Style?

3:Personal preference towards certain guitars?

4:Type of Amp you own?

5:do you own any pedals/distortions?

P.S. I agree with petrucci, once you use a wizard II, its hard to adjust to using a standard neck. Thats not a bad thing though, Wizard II's are great necks, and Ibanez makes a lot of great guitars.