You might need to learn how to use the lumbar adjustment properly, and I'm not trying to sound condescending. I used to get LBP from my seats until I learned how to use that air bladder properly.
E92 335i: Space Grey|Coral Red|Aluminum Trim
Hold out for the BRZ STI or... Rocket Bunny FRS. Update: Scratch that. I've got a 2015 5.0/6MT with my name on it.