before turbo, WITH cams, headers etc I was running 15.0's at 80something MPH
Gas mileage only went down because my foot was in it more. I think it actually improved if I drove easy. I know that sounds hard to believe, but I went from 26 to 28MPG on long highway trips. However that could have been due to the exhaust and intake work also.
As far as the ONE stock cam I have, sure, you can have it for a low low price of... well.. we'll figure that out.
Oh yeah, my RS is an 01 with SOHCs (which I like more for a list of reasons)