I've found mine to have a bit more ooomph with the upper resonance flap disconnected, but it may be anomolous to this car.

Anyway, they're just as "fast" as the older turbo'd ones, with slightly better mpg. Only bad point is the long bodied GP's.

BTW, if the vacuum pump hasnt been changed out, it is recommended at 250K. They go without warning and can really mess up the engine internals. FWIW. BTDT.