Have been driving BMW's since 1972. Most uncomfortable drivers seat ever. Purchased new E92 335I 6 spd with M Package in Dec 2010. Have been battling a problem with the rear section of the drivers seat bottom feeling like it has no support, feels like sitting in a hole.. Dealer has made unsuccessful attempts to fix, regional factory rep says its within acceptable spec (not his backside spending 2 or 3 hours feeling very uncomfortable driving the car ). My service writer mentioned he heard from an owner of a 335IS with a similar complaint.. Just registered complaint with BMW NA. Anyone else with similar problem???