Most of my car will be built with parts from
Bavarian Autosport and
Turner Motorsport. Turner has some great racing and performance parts, and probably the best prices on some of these, but thier customer service is lousy at best. I honestly hate doing business with those yankees, but they honestly are so much cheaper that I simply put up with it.
Kudos to
Bavarian Autsport!
They are the best online BMW retailer IMHO. They have an excellent web site and carry probably the largest selection of OEM and replacement parts (and some performance parts) for our cars. Thier service is excellent and the parts are always top quality. Also, I know it's a small thing.. but the fact that they use actual BMW part numbers to identify thier parts makes things so much easier when you are rebuilding a car to the extent I am.
Autohaus AZ is significantly cheaper on a few items (like sensors), but they damaged a few parts in shipping and a few other parts were "no name brand" parts. I wont be doing business with them again.
BMA Parts is also excellent, but thier selection of replacement parts for the 318is seems selective.
Just my $0.02 worth as I've dealt with most of them.