>yeah i was wondering the same thing, how would a 2.5"
>exhaust be advantageous when the downpipe is still
>restricting me to 2.25

Thats one of those questions that most will never be able to explain other than "the dyno said its better". In most cases its just more powerful with a larger exhaust even on turbo cars with small stock downpipes. In reality though the difference between 2.5" and 3" cat back on a 200 something hp turbo'd car under 10psi is only a few hp (I know cause "the dyno said so" ,somebody elses dyno anyway).