Did a tune up and installed bpr7es ngk's. At first I didn't gap them and had a horrible misfire. Gapped them to .025-.026 and it's much better but I'm still getting a mild misfire while hitting boost. Should I gap them even more? Before I gapped them they were roughly at .030.

 

Gap them tighter. I run the same plugs gapped to .020. You don't have to go that far if you don't want to but see if a tighter gap will help. I have no misfire issues running the stock turbo on 93 octane with a max of 25psi.

 

Gap to .020". If that doesn't work, time for new coils.