Quote Originally Posted by sharmut View Post
I believe a slight shim is needed if using the slider. It's to allow clearance for the slider's locking mechanism to unlock. Otherwise, the lock contacts the seat's side bracket and won't release.

Doug suggestion to position the slider on center between the top and lower half of slider worked for me. With the slider in this position it reduces the amount of play within the slider between it's upper and lower half. Even in this central position, there is still some play although considerably less. What I found while on track you don't notice any play when you're strapped into a harness.
Quick update on this, I removed extra shims and test drove the car. While it improved the stability, it was not as stable as I wanted. I ended up removing the slider and directly bolting the seat. I didn't have a chance to drive it yet but the height drop made the sitting position better for me.

Seat feels nice and rigid, can't wait to test drive tomorrow. Now need to wait for the passenger side bracket