Thanks for the response.
I'm led to undertand that the increase in k/w is at the top end, and that the freer and less restrictive the flow the less back pressure, this in turn neccessitates less response and and bigger turbo lag.
I would appreciate feed back from any one who has undertaken the dump/front pipe with a hi flo cat, to see if their has been better throttle response and less turbo lag.
The issue with some of the dyno figures that are given and the gains attributted to the dump and hi flo cat is that it focuses on top end and the k/w gain going flat out, at hi to maximum rpm. A good street car is one that can give the best overall response, and linear torque through out the rev range, not just a large burst.