So after witnessing a bad accident at the track this fall that resulted in the driver suffering a traumatic brain injury, I'm doing a little Christmas shopping for head and neck restraints. I have an R53 with stock seats and Schroth Quick Fit 4 point harnesses with the seatbelt-style buckle that I bought in 2008. I've looked at the HANS Sport model, the DefNder, the R3, and the Hybrid Rage. All have pluses and minuses, and several people have given me great commentary on all of them. Right now I'm leaning towards a HANS or DefNder due to the superior range of motion and crash test numbers (all are rated for SFI 38.1, but these exceed the standard). Does anybody have any experience with using these things with a 4 point harness? It came to my attention that my harnesses might not be compatible with a HANS-style device.