I have milled those over myself. They look decent enough and you can't argue with the price.
Two considerations; IIRC, SCCA requires FIA certification for aftermarket seats...maybe someone can verify if that applies to NHRA too. FWIW, I didn't see verification that they had this certification...maybe I missed it?. Certainly it doesn't mean that they're unsafe but sometimes these things are a good baseline.
Second, If you do plan to use the shoulder harness feature, you'll want to measure your hip to shoulder length and compare that to the measurements on the seat. If you're too tall, the harnesses will do some real damage to the ol' skeleton in a crash.
Keep us posted!!