Sorry Jamie, don't know the rules up in Canada, but in the US, a 'SNELL' rating has nothing to do with legal or illegal (in terms of street use). While all SNELL helmets are DOT (US department of Transportation) certified, not all DOT helmets are SNELL certified. The SNELL rating is stiffer than that of the DOT. To the best of my knowledge (again regarding legal/illegal in terms of street use) once a helmet has received DOT certification, it is always DOT certified - although I expect certain states may have serviceability requirements as well. Personally I find the entire thing pretty damn annoying as I purchased a really nice motorcycle helmet while I was stationed in Europe, and I would stake my life (I do) on the fact that it is at least as good as anything we've got in the US... but it is no good for the track. Sorry if I took your legal/illegal out of context and it was meant specifically in regards to track applications.
Paul - regarding the FAQ... honestly I'm not sure that there is a great deal of need for it to be in great detail, at least regarding weight and things like that. While it may be a big deal for a motorcyclist to know how much a helmet weighs, for the ... maybe 2 minutes? a 1/4 miler is going to be wearing his helmet, the difference of a few grams most likely doesn't matter.
One thing it might be good to point out is that if, when looking to purchase a helmet, the purchaser can't find a SNELL certification, it could be that the helmet is in fact, NOT SNELL certified... Also, when in doubt, you can always ask the person selling the helmets for the brief. Otherwise, I expect that the major helmet manufacturers websites would have details on what makes one helmet different from another.
Further information can be found at these websites:
Snell Memorial Foundation:
http://www.smf.org/cert.html
Snell purchase guide:
http://www.smf.org/top4.html
Automotive and Motorcycle Helmets:
Bell Helmets:
http://www.bellhelmets.com/
Bieffe Helmets:
http://www.bieffeamerica.com/
Motorcycle Helmets:
Shoei Helmets:
http://www.shoei-helmets.com/
HJC Helmets:
http://www.hjchelmets.com/