Pushing 30psi through stock heads, is some extremely inefficient boost, and its killing your turbo. You're way out of the zone on the compressor map....totally overheating the air and also thinning it out to where 30psi has not too many more o2 molecules than say, 25psi. Get some big heads. You can drop the boost way down and still pump the same, if not more air. Plus with the cooler charge, you can run more timing and less octane.
I'd make that my priority instead of a catback. The heads are the bottleneck with your combo, not the catback. The hooker catback, by the way, is cheap and pretty nice system. Sounds good and flows really well. Just dont get flowmaster anything. Especially on a turbo car. They truly are NOT Flow masters. Personally I love magnaflow catbacks. They'll outflow just about everything, yet they're very stealthy...real quiet until you open it up, and with a good 3" downpipe, a 3" testpipe (no dump) and a magnaflow CB, you'll run just as hard, if not better than an open dump.
Then get yourself a good 3" DP and a test pipe. This