Helmets - Fiberglass Shell vs. Carbon Kevlar

[The ModFather]

So I'm trying to decide between the Ducati Dark Rider Helmet by AGV which is a Fiberglass Shell and the GP-Tech which is Carbon-Kevlar. As you probably know the GP-Tech is almost twice the price but is more plush with better venting and is their top of the line helmet. Does anyone know if there is a substantial difference in protection with Carbon-Kevlar over Fiberglass? I can always throw some Ducati Decals on if I want to so thats no selling point and they are very similar looking. Just trying to determine if it's worth the additional coin for the GP-Tech. Any insight you can provide on either or both of these two helmets or Fiberglass vs. Carbon-Kevlar would be greatly appreciated.

[thought]

As long as they are all DOT/SNELL approved they will all protect the same.  You pay the premium for less weight and venting... get the one that fits better and you'll be happy.

Also, keep an eye out for some discounted Rossi helms... the yamaha colors were going for pretty cheap a while back.