I traded in my 02 for an 03. The 02 seats were fine. This is the fully adjustable leather I'm talking about. The seats in my 03 (also leather) have caused me a great deal of pain. They made so many changes to the 03 seats that, in my case, were not good. Understand, I HAVE NO BACK PAIN WITH ANY OTHER VEHICLE!
First, I went to the dealer. . . forget getting any help there.
Then I went through GM Customer Service . . . completely useless.
Then I went to an upholstery shop. They gave me some upholstery foam to put on the seat bottom and back and told me to try it many different ways and to cut it up to fit. Some improvement, but not close enough to being comfortable.
Then I went to a back pain / orthopedic specialty shop. They had lots of seat pads and devices. I tried them all in the AV and could not get the proper fit.
Then I went back to the upholstery foam. I finally got the right combination of foam pieces going to get a pain-free ride, but it looks like @ss. I could get the pieces installed in the cushions, but they wouldn't function the same. So, I'm just leaving the foam pieces on the seat. Not real happy with the stock seats in a 42k vehicle. One consolation though, is that the upholstery place says they have found that customers have the same problems with luxo vehicles like MB, BMW, Lexus, and Caddy. The bottom line is that no manufacturer can make a seat that fits everyone just right. YMMV