I have been dealing with these guys to help build what I need for my M3. They have been extremely helpful in every aspect of the build and installation. I don't think I've ever gotten this level of service from any other performance vendor, and I've been doing this for 20 years. Their products are well thought out, designed with top notch materials, and work as advertised. I couldn't be any happier with the way my M3 handles, and the ride is quite comfortable considering the performance gains. Overall this company provides excellent value for the dollar!!!