I have the Clazzio and I think it more for looks and seat protection.

This guy did a DIY on his seat. http://www.crzforum.com/forum/inter...um/interior-ice-discussion/9568-low-back-pain-easy-driver-s-seat-angle-mod.html

 

I feel it made the stock seats way more comfortable, as well as looking great. I've had mine for a couple years too. I have PVC black with blue stitching and the Honda H embroidered in blue in the head rests.

 

I installed my Clazzios a couple weeks ago and love them. I also did not care for the factory seats as they were uncomfortable for long drives. The Clazzios do improve how comfortable the seat is now. Its not like changing to a Cadillac but the hour and a half long drives are easier now. I added heat with mine and even when its not real cold out its nice to have them on the lowest setting.

 

The clazzio seat covers have a 0.5 inch thickness of memory foam. So they may be SLIGHTLY more comfortable lol. Mostly for looks though.

 

This Obus thing has had good reviews:
http://www.crzforum.com/forum/general-discussion/8910-i-need-more-lumbar-support-2.html

Kind of depends on your luck, and where the seats bother you. I'm lucky, they fit me swell. Three times down to LA from Sacramento for a concert, watched the concert, drove home. Loved the car the whole trip.

There are a couple more seat comfort threads, search "back cushion".

 

Just went into their website to look (out of curiosity) and it looks like '14 is the last year they make them for the Z.

 

Have seats changed much between the years?:dunno:

 

The bumper caps, some interior stuff (electric parking brake, armrest) and experiments testing just how ugly a road wheel they can make have been about the extent of "changes" in the Z. Other than those, after-market parts mostly fit all years.