ive had a 83, two 86, and a 89, 88 or 89 are the best, 83 and up ride on the e28 frame, 77 through 82 ride on the e12, 635 came out in 85, 3.5 engine but cars also got heavier, 88 and 89 they had a lot of inprovements, bigger engine, faired bumpers and elptical headlights and foglights, also all leather interior like a L6, which was only sold in 87, there great cars, very easy to work on and share many parts with e28. at 80 or 90 miles a hour rock solid, buy a western car, no rust, if it has trx tires make the seller take a thousanf dollars off, thats about how much it will cost to replace them and there outdated, was voted by automobile mag as one of the 50 greatest cars of all time, im already looking for another.