So i'm planning on buying a new guitar (mostly for instrumental/prog metal, like John petrucci, Joe satriani, etc), but i have had little luck finding one that i would want. All i know is that it has to have a locking trem, 24 frets, and at a bridge humbucker position. i want to put in some dimarzio pickups later, so the pickups itself are a non-issue.

so far I found two that have peaked interest, but have read mixed reviews on them. The first is the Ibanez JS-100, which i can get used for $450 (im pretty sure i can get it for less, but that is what the tag at my local store said). I tried it out today and it sounded great (good distortion, great harmonics, etc), but i've read that the locking trem is not so great on it and it goes out of tune easily. i didn't experience this, but i only had time to play it for about 15 min. so i don't really know. it felt great in my hands as well. The big problem with it is that since it is used, the truss rod need to be slightly re-aligned, which im hoping the store can do for me.

The other one is an ESP LTD M-100 or M-103 (the only difference is that the M-103 has a middle/neck single coil instead of just a neck humbucker). I have a great history with ESP/LTD products, and i really like this brand. I tried out the M-100 at my store, and it sounded pretty good, but not as good as the JS-100. I figured that i could bridge that gap easily with new humbuckers. But the main difference is that the bridge was nearly impossible to keep in tune, even as it was new. However, i can get this one for only $289 and buy upgrades to fix this.

My questions are these:
-Which one would you go for?
-Have i not seen another great guitar with these specs at a great price?
-How easy is it to install a better bridge on one of these guitars if i decide to go on the Buy cheap/install upgrades route?

in case this helps, i am using a mesa boogie f-30 and dont plan on changing amps for a very long time.

any help would be great

ps if i need to post this elsewhere let me know
Try to find a used Rg 570 or something similar, it has the Edge tremolo which is really good.