I've got a stock non-M 2.5i I've owned since new 2003 and am impressed with your wheels. Truthfully, mine has always been a street-only ride and I'm looking at 18" diameter. What setup would you recommend and does tire size affect availability and options when buying rubber?
Also, would you recommend the ARC-8 or EC-7 for a street Z4? I really don't understand the difference between the two. Thanks!