rate this stuff for add some horses on a 318

Sounds like a fun little car!

I think you should consider 3.5 gears with a 26" tyre - its a nice compromise between street and strip - and will hold a 70 MPH cruising speed at around 2750 RPM which won't kill your valve springs with with your cam.

Just don't expect to keep up with the M3s and the AMGs on the "Bahn" ...but it'll scare the 335's in the back streets ;)