Well, I've got the 7 psi Powerdyne (soon to be a 9 psi Powerdyne, LOL) and I am running JBA headers, the SLP y-pipe, a Dynomax 13.25 Super Converter, and the 2.5" Dynomax Ultra-Flow cat-back kit.
Why so simple, you may ask? Well, contrary to popular belief, these newer engines don't work like the older hi-po engines -- they require backpressure to fully utilize what they're getting. If you open up the exhaust too much you LOSE power (i.e. you may have a gross gain of 30 rwhp, but because it flows too freely you lose 10 rwhp elsewhere -- not to mention the torque you lose, so you actually only have a net gain of 20 rwhp). If your exhaust escapes too quickly there is no time for the motor to build up the high combustion it needs (especially in a forced-induction set-up). Therefore, while 3" true-duals all the way back may work relatively well for N/A applications, it is not as good for forced-inductions. Also, if you free it up too much you will lose rw torque as well -- which we all know is directly related to acceleration. So, you need to keep some of that back-pressure bottled up (but not too much, obviously). Also, if you free up exhaust flow too much you run the risk of damaging your heads (or head gaskets) and fouling your plugs more quickly. Also, I noticed a mention of an X-pipe -- that is not a good idea for forced induction -- it works absolute miracles for N/A, but supercharging is a realm of its own and a lot of rules don't apply (of course, a lot of us make up new ones as we go!).
