I was installing some Apex Low Profile safety selectors on my Evo today (figured I should do it now so Buhler Ballistics has one less thing to install for me later) and noticed that my trigger case was loose - it was nice and snug on "safe," but the moment I removed my safety or even put it on "fire," the entire trigger pack would move slightly within the lower receiver.
I figured out that this was due to the trigger case screw coming a bit loose. Mine was a welded lower that Shooter's Element drilled out, cleaned up, and sent back, and it's been shot a bit since then. My line of thinking here was that the case screw had begun to loosen under recoil now that the weld was gone and no loctite had been applied (my trigger swap lower, while not welded, clearly has more than a bit of loctite applied to the case screw and isn't budging). Tightening the screw down took out the play, so the problem seems to be resolved for now.
The reason I bring it up is that depending on who did your trigger pack drill-out (and how) your trigger case may end up moving a bit more than mine did. Be sure to check it periodically, as I suspect the forward/backward play might eventually lead to light strikes or other issues - perhaps even an OOB discharge. Of course, it's possible that the acceptable tolerances are wide enough that this won't be an issue for anyone, but it can't hurt to check!