The issue: Car is hitting what seems like a redline around 5500 rpm when making any amount of boost over 13lbs.

Back story: Recently upgraded turbo with raw brokerage pro mod, installed AEM V2, map sensor convert, changed AEM CAS trigger disk, upgraded 550cc sti injectors.

Attempt 1:
The first day on the dyno the car had no issues pulling and making power to normal redline at stock boost around 8lbs and also 10lbs. Once we turned up the boost with my MBC to say 13lbs, the car would cut and break up around 5500 rpm almost as if it were hitting a redline and wouldn't pull any further. No amount of adjusting timing either way, playing with tps values would fix the problem. We tried gapping down the plugs, no change, swapped the coppers for iridiums, no change. Even though they are new splitfires, I tested my coils and they test okay. I cleaned up and even added various grounds to the block, head, and chassis. All to no avail, anything over 10lbs the car would cut out.

Attempt 2:
I got a new CAS from raw brokerage and swapped in a new aem cas wheel as well. This is where it gets interesting, 8lbs was good as usual, 10lbs good as before, so we turned it up to 13lbs and to our surprise it pulled all the way to redline with no issues. But then like the first day anything over 13lbs now the engine cuts around 5500 rpm. Again no amount of timing adjustments could remedy, we even did a pull and made it so the tps was reading at full 5v WOT in the computer just to rule out the tps and it made no difference. What we are confused by is why the new CAS would give us another 3lbs of boost and 50 odd whp but the problem still persists at now even higher levels of boost. Timing was checked and set to 15 degrees both days after the CAS was reinstalled.

We are at a loss as to what the problem could be, the data between a good run and a bad run look similar and we cant't pinpoint any deviations. Before upgrading the turbo the car ran absolutely fine tuned on the stock turbo running 8lbs with an ancient hks safr and stock computer. Also before putting the car on the dyno the very first day, we checked for boost leaks with a boost leak tester and fixed all that we could find.

Car mods:
Rb25det series 2
Raw brokerage pro-mod turbo
AEM V2 w/ trigger disk swap
3.5 bar map sensor
IAT sensor
Walbro 255
Tomei FPR
550cc sti injectors
isis 3" straight pipe
FMIC
Freddy intake manifold
AEM wideband
Splitfire coilpacks

I've tried searching and couldn't find anything similar to my issues that weren't easily solved by the usual coilpacks, CAS, TPS. If anyone has any suggestions on where we should head next please comment, I'm open to any suggestions.

Bump for any ideas??