Differences between euro 635 and US 633

[WALSRU]

From a performance standpoint I'm trying to find out the differences between these cars. Most places such as bavauto, bmpdesign, and turner only show parts for the 633. So I wanted to make sure most of it is interchangeable. Would a cam for a 633 fit an 80 635? Are the shocks, springs, and sways the same across the model range? Motronic didn't occur until 82, would I need adjustable fuel meter/calibrator to do the same job as a chip on a later car? Also, I just read the pre 82 had four pot front calipers and all vented discs : .

*deep breath* . . . Any ideas?

[Aaronl]

I have a 79 635 csi euro Most parts are interchangeable. Bavauto can cross reference. currently changing my rear wheel bearings and their the same. shocks and springs were the same. my front discs are not drilled yes on the 4 piston caliper. Hard parts are some of the body and trim parts like the rear rubber spoiler.