I agree raising the comp is the best thing you'll Eva do to your 4a turbo. Aslong as you got the right a/f ratios and good amount of boost you'll superceed the low c/r 4agte running 17psi.

Head gasket is the easier option but might aswell do a small skim.
I have plans for mine if it fails soon, raise the 8 0:1 c/r to atleast 9 0 :1 for more response with less boost.