Don't think it makes a difference. If it did they'd all have aero hump's on em so they could market that "little extra bit of safety," too. X-lite's are top helmets, and there have been plenty of people knocked out cold wearing any brand of helmet. So no, IMO it doesn't matter.
2006 ZX10R, 176whp & trac control
2002 Aprilia Mille
2007 CBR600RR (the gf's)