Bill,

You might not think you need the SA rated helmet, but you need to ask yourself just how much you bel9ieve your head to be worth. As for sizing, as a long time racer (NHRA,SCCA,etc), I HIGHLY SUGGEST that you find a local shop with trained employees to properly fit a helmet to your head. Each brand, and each style of that brand fit differently.........Again ask yourself how much your head is worth and go from there.

Bill