The 2001 Phase-II cars may be better in this respect, but the final silencer on my 1998 T4 was the biggest source of backpressure on the entire system. Just replacing that gave a much better feel when opening up the higher rpm's under full boost. Turbo's hate backpressure. Sorry, don't have any dyno data.

Of course the 2 1/2" stainless TME catback system I'm now runing is even better in that respect. It pulls strong in 4th gear all the way to 125mph (top end used to lose power pretty quickly with the stock exhaust). Top speed in 5th depends a lot on the outside temperature. Lower=higher top end, but it does at least 150mph.

Another thing to keep an eye out for (and perhaps something to install in the car) is the exhaust/turbo temperature with an upgraded ECU program and higher boost. If it gets too high (add an EGT gague and a boost gague) it means you need a better flowing exhaust and (biggest gain in this area) downpipe, because the hot gas isn't removed quickly enough. You don't want the turbo or cat to overheat as that can kill them off pretty quickly.

Bye, Arno.