I'm considering one of these harness systems and looking for input. No cage in the car at this time, most likely a Tiger Cage in the future. In the interim I need better upper body restraint and these appear to be the best options and will work with my lower-end Recarro seats with detachable headrests utilizing the inboard rear seat belt mounts.
I'm leaning toward the Sparco's as they would utilize the current Simpson belt mount eyelets.
Thanks