With reference to the system we in the DOC UK are having made: 1) The main problem with the stock system is that the piping is rigged to get the exhaust through the cat. Remove the cat, and why bother with all the rest of the crazy pipework. Our system will replace the manifolds and feed them directly (no cat) into the back box, which will look exactly like the stock one except for having a inlet on both sides. I personally do not intend removing the lambda system. 2) The "noisiness" is up to you - these are made to order and you can specify as quiet or loud as you like. 3) The lack of cat is bothering you guys a bit. Remember the first generation Island Twin Turbo and the BAE turbo systems got rid of the cat. 4) The cost is around $1200 + shipping. Martin #1458 William T Wilson wrote: > On Fri, 10 May 2002, nbrommer2k wrote: > > > What is the legality of such a free-flow exhaust in the US? And what > > kind of repercussions would such a system have on emissions tests?