Sorry this is an old thread. My back gets sore very quickly. Love the car, hate the manual sports seats! I gotta find a solution or I am going to go mad. I tried the lumbar support in a car with them built-in (at the dealer) but it didn't hit me in the right places.... Not for me unfortunately. I thought the lumbar support was too hard. I went to an auto upholstery specialist and had some cushioning put in the lumbar region, but unfortunately I was not present when the work was being done and consequently its still not right. In hind sight I should have had the whole thing custom fitted while the the covers were off. So gotta go back and have the seat cover removed again ouch!!! The problem is the seat back is actually curved in a c shaped way - the shoulder area curves forward causing contact across my shoulder blades. I guess there are ok for short small framed people who might sit a little lower in the seats. I really need to completely start from scratch and get the right curve and support. I really like the seats in the Z4. They are nicely angled and supportive.