Pic of Infini knee pad and Infini IV seats in my car for reference.

I'll also be posting more info on mounting infini seats with some tricks and lessons learned during the process of installing them. ex: How to clean the seat's fabric/stain removal, defuzzing the suede, rust conversion/removal of rust on the bottom seat pans, factory seat belt guide with these seats, and the different seat bracket issues I had. (Not all US Rx-7 seat mounting brackets are created equal; even though the parts diagrams use the same part numbers for S4(86-88) and S5(89-91) .

The US Passenger Infini Seat requires a US 89-91 seat bracket if your seat didn't happen to come with the stock infini jdm driver one. Reason being, the US 89-91 series seat mounting brackets had smaller tension adjusters which will clear the bottom of the infini seat pan when sliding forward and back. Some drilling of additional mounting holes on the brackets were necessary to line up with the infini mounting points. The US brackets also allow a larger forward and back sliding distance at least on the US driver side bracket vs Infini Bracket I tested.