"M10" is the engine designation for the BMW 4-cyl in the 320i. IIRC, the reason for the different spec lines is that there was an engine displacement change mid-way through the 320i life-cycle. The early 320i had a real 2-liter, the later cars were actually 1.8-liter - all carried the M10 engine code I believe (but I could be wrong about that). You need to make sure you've got the right spares - you can only update/backdate within the spec line, meaning you can't put an early 2-liter into a chassis that was supposed to have a 1.8 (must be same body and engine for update/backdate).

"2002" refers to the venerable BMW 2002 (1968 - 1973 and 1974 - 1976 - slight body changes, so different spec lines IIRC).. Similar in engine to the ealry 320i (except carbureted in ITB trim), and still competitive in some parts of the country, but body panels in general are getting hard to find, and rust-free panels even rarer - it is a nice, simple car to race though (my first IT car was a '71 2002)..

Bob Smart (Smarty's Auto and Northeast Racing Enterprises) is a 320i guy. He's got both ITB and Prod car experience with the chassis (Bob's also the "Hoosier guy" for NER events). The last e-mail address I have for him is [email protected].

Good luck.
-noam

p.s. order a hard-copy of the GCR and get out a highlighter to note the things you have questions about. Remember, if the book doesn't specifically say you CAN do something, you CAN'T..