Lightweight helmets are a great investment however you need to understand what you are buying. This is a motorcycle helmet (Snell M rating) and not designed for impacts into roll cages, steering wheels etc and is not flameproof - no M rated helmet is. Snell SA rated helmets are designed for car racing. Australian standards stickers are really only applicable if you want to use it on the road - Snell, SFI or the Brittish standards are all fine for track work.
As for buying helmets sight unseen - I bought mine from an overseas vendor, the size wasn't perfect so I bought the next size down as well and sold the larger one on Ebay. Got the dome for 1/2 the local price......
