I see. But with the extra power, albeit 10BHP or so , there must me a fuel cost. Perhaps its such a small performance gain that the fuel hit is small too. I thought, but perhaps wrongly (as all I know about cars has been learned since owning a Scooby), that the cat-less pipe allowed the by-product to be pushed out easier meant the turbo was spinning a bit faster and earlier therefore more compression and thus more fuel. I'll bet I have just made myself a laughing stock, haven't I?
J