Just get a downpipe, (upipe too since you have a catted 02 up) exhaust, and a stage 2 ECU re-tune from XPT or Cobb.
Don't go any further then that unless you plan to actually do a ton of homework and read pages and pages of how other people built up their cars, otherwise you'll just get yourself in trouble up ess creak without a paddle.
If I'm wrong, someone who actually drives a turbo car will correct me... I'm just parroting back what I've read, too busy racing in the dirt :shrugs: