not that you asked me....
but.... most tracks do not recommend or accept motorcycle helmets. they do not meet the same requirements, by a long shot. Now for casual tracking, motorcycle helmets have been accepted by many tracks; but for what i consider driving experiences, high speed track events, i prefer a Snell rated (appropriately) Racing helmet.
I found a good quality Bell at the Smiley's in Mesquite. The 'kevlar' Simpsons are very nice, but $700 and up. wow. I just don't think i'm on the track enough for that. My Bell was just under $300 I think. will have to get out my receipt. They are fiberglass, and if you don't know any differently, the fiberglass is just fine. I think it would be hard to go from a Kevlar (very very lightweight) helmet back to fiberglass.
just my $.02 worth!
Kristen