Seraphim777

I have a 2002 Subaru WRX (US Version) and am wondering what would be the best way to modify my exhaust system. If I install a turbo-back system with a high-flow cat and an uppipe with no converter will I lose all my backpressure needed for spooling the turbo? I want to mainly increase my bottom-end performance gaining high end isn't nearly so important, but I don't want to sacrifice too much of the top end either. Currently I am planning on installing the exhaust system, a cold air intake, boost controller and ECU this summer any other ideas as to what could help that doesn't mean tearing into a brand new engine?