I see. I would probally see some sort of performance gain personally, seing as how my 318's exhaust system is shot. LoL. You can easily hear exhaust leaking all up behind the rear wheels. So I'm sure thats letting some of my power go. But I wasn't sure how good of an exhaust system I already had, so I was considering upgrading if it was posiable. What about a high flow catalytic for the e30 series? also, will any head designed to fit the 1.8l engine fit my car? I have the 1.8l so I mean I would imagine so... but I'm not sure, is there any horozontaly mounted engines in the bmw family? Like in a 4wd version? Anyhow thanks for replying at least.