The BMW Z3 seat was not perfected from an ergonomic perspective. Drivers both short and tall often find themselves at the limit of the "tilt" adjustment, but still wanting for more. 

A hardware bin solution was presented to the community years ago using components sourced with low cost in mind, rather than durability. They greatly increased the comfort, supporting your thighs and providing a better angle of the driver relative to the pedals. But these kits are starting to exhibit failures, damaging the sheet metal where the seats mount. A better solution had to be found...
 
And found it was, by the enthusiasts on the Z3 forums at bimmerforums.com. Multiple ideas were thrown out there until settling on the current, pictured design, from user kornfield. A group buy was quickly established and reached over 30 sales very quickly. 

Link to previous discussions and forum thread can be found here: https://www.bimmerforums.com/forum/showthread.php?2479768-Upgraded-seat-tilt-kit-group-buy-feeler
 
A standard kit includes enough for both front seats (four risers)
-4 risers
-4 class 10.9, flange head, zinc plated bolts
-8 washers (these function solely as thin spacers to ensure the top bolt can be fully tightened)
 
One kit = $140 /kit
Two kits = $130 /kit
Three kits = $120 /kit
Four kits = $115 /kit
Five kits = $110 /kit
Kit for one single seat = $80/set of 2 risers with hardware
 
Kornfield was not keen on distribution and shipping and dealing with everything which that entails, and not wanting this design to end up in the bin over this hurdle I stepped in to help manage that side of things. 
 
Each kit includes:
4 seat risers (enough for both front seats) machined from mild steel
4 class 10.9, flange head, zinc plated bolts
4 washers (these function solely as thin spacers to ensure the top bolt can be fully tightened)
 
This pricing is the group buy pricing and may increase in the future
Pricing breakdown is as follows:
One kit = $100 /kit
Two kits = $97.5 /kit
Three kits = $95 /kit
Four kits = $92.5 /kit
Five kits = $92 /kit
 
Please note - use code "KORN" to correct the shipping cost