Just a note about firesuits and the required ratings, as I had it explained to me over some "refreshments" at Bonneville because I was all fired up over it at one time also.
Seems the "other" racing organizations have shorter tracks, 1/4 mile, 2/12 mile ovals, and quite a few more safety vehicles and worker's available in the event of a mishap. Whereas LSR is a couple miles at the shortest, to 9 miles at Bonneville. Also, combine that with high speed at which we travel, 300MPH = 1 mile in 12 seconds. It takes longer to get stopped and possibly longer for help to arrive at the scene. that is why you find LSR Safety requirements to be more stringent, and higher levels of fire protection required and even more recommended. As for me, my best speed was 150 MPH, I went with over 200MPH rated firesuit gloves etc.. for the extra protection.
It was expensive up front, but worth the extra safety for me. I just had my Simpson gear re-certified last year, $50 , I'm going on my 7th year in this getup.