I worked together with MPP on this and have been testing the product for well over a year. I've put about 20k miles on it (including One Lap of America).
I installed the OMP Champ-R. What I really like about this solution is that it maintains (almost) all of the features of the factory seat. The occupancy sensor works perfect, I still have the OE pre-tensioner, seat belt, and buckle. I can use easy entry so getting in and out isn't a nightmare. The only thing I "lost" was the seat heaters, but there are some aftermarket seats that offer that.
No errors, functions as far as the car is concerned as a factory seat (no issues with Firmware updates). As far as use on-track, it's (as expected) far superior! I don't feel any need to use a four-point harness now. The OMP keeps me right in place and I'm no longer fighting the car/steering wheel. Vastly better experience and I don't feel beat-up after a session haha!
Installation is fairly easy and reversible. If you're looking for a fixed-back seat solution, I think this is it!