Thats how I understood it... BUT thinking about isn't that how a Gun silencer works as well, and the bullet leaves the gun at a slower velocity when one is used.... So if Gas speed is slowed down then back pressure is up and power down yes???

To be honest though I don't know! I always thought that with enough silencers you CAN shut up a car WITHOUT loosing power.... maybe I am wrong though???

We clearly need someone who KNOWS for sure though...

Good post Phil, see you can do them!

all I know is my car was alot quieter AND felt alot faster once I got rid of the mongoose!