P0234 Overboost and low compression

[G3nwonMazdaratti]

Hey all. I'm from the Minnesota, north metro area. Back in November I purchased a full built and bolted speed3. Forged internals and all that good stuff. Parts list includes,
bnr s3,
Grimmspeed ebcs,
88mm Wiseco pistons,
k1 rods,
3.5" HTP intake,
3" catless dp cbe,
Autotech HPFP internals,
Cx-racing fmic,
Damond TB spacer,
jbr Im spacer,
Kozmic egr delete,
Go fast Bitz blows off valve recirculated,
occ set to vta under boost,
c-pe safe seals,
light weight fidanza flywheel, banjo bolt,
sure short shift plate, streetunit rmm,
ngk 6510 spark plugs,
3 bar map sensor,
IM flap runner delete,
jbr bsd oil baffle..

The car had roughly 33k miles on the reman build. It was freek tuned by Justin through the accessport on e33 making 400whp.

Just recently I did a compression test. And I have low compression in all cylinders, (roughly 140 across the board). The issue started when I hit over boost one time a month or so back. I have a slow turbo spoil and have already diagnosed that there is no shaft play on the turbo. I replaced the ebcs, my bov, all my intercooler couplings and clamps. Multiple boost leak tests on hot and cold side. So I have no idea what could be causing the low compression or spool delay. I have yet to try a new tune and plan to do that next.. Any suggestions or other routes I should take..? Thanks.

Andy