I just got a loaner 328 with manual seats... these have less adjustment than the seats in my 135 (3 way vs 6 way per my earlier post). I would guess the difference is that I have sports seats in the 1.
The 328 (non sport) seats are awful. Not just for adjustment, but just awful in general. NO support at all!!!!
If this was my only exposure to a BMW I would never buy one. If you go into a dealership to check something out make sure you check it out apples to apples.