Single layer Racing Jackets

I have read about single layer racing jackets recently from reading about drag racing safety.  The jackets are supposed to be  certified SFI 3.2A/1.  Would that pass the scrutineers for SCCA/low-speed lapping? What is the intended use for that?  Should I expect it to be bulky or heavy?   I was considering getting one, because they are not to expensive (about $60) and seems a practical piece of safety gear for certain low-key events, like lapping, rally, etc., or just as a fancy windbreaker for the car, and would probably be better than  the old-fashioned boron treatment.

Edited December 11, 20168 yr by TomoHawk