I am thinking about purchasing a "635 CSi". I have no history with BMW, just have always felt the 635 was one of the best looking cars ever made. I have a late model Nissan 300ZX that I am going to paint, do some engine work on, etc. Thought this might be a time to consider buying a 635 to use as an occasional driver. I have a truck to drive for bad weather so both cars would be fair weather cars. Is there a site or book that anyone would suggest to get me started in understand the different variations of the 635 available. Not sure what model are best, or even the last year they were manufactured. Some pointers please.