I have experience in stock LX, SMA hiflo y-pipe and 3" SS cat-back, and CTA hiflow 2.5" Single CTA custom. To be honest, when the 3" was welded correctly and the flanges weren't leaking, my car performed better than either of the other two setups.
I had no resonator on the 3". It was loud as hell, droned like a b1tch and easily outperformed my other setups. In the KC Nats chart...Dan's 98 SVT outperformed another 99 SVT after 3200rpm........so if you drive it hard and keep the revs up, 2.5" is not gonna be too bad, since 3" is not that detrimental.
I'd say a 2.5" Quasi dual with no res would be just about ideal for Flow / Velocity / Performance. Just my opinion backed by at least one year of living with each setup.
The Dynomax Race Magnums part #24215 are loud, little to no drone on the freeway though. I think it is a little "farty" but a few people have said it sounded sweet. I have one as a res and one as a muffler. $39.03 shipped to my door.
Hope that helped.
Ed
95 LX V6
Dyno Chart..........Check 99 KC Nats tab
