Ted,
We accept only SFI ratings, in your case, somewhere between SFI 3.2A/10-20, depending on your speeds expected and the engine configuration. Ask around the various LSR websites or Ebay, used is cheaper, just beware too good to be true stuff.
Again,it's all in the Rulebook. The scariest part of LSR to me was passing tech, driving 200 mph is not comparable. Be sure the car is ready. SAFETY is the focus.
Bob Wanner