If your a size Large in the Gp-Tech,then you would be the same size Large in this Pista GP. The inside shape is slightly different,hugging your skull more. You do get a moon shaped piece of foam that slots into a pocket at the top of the neck area,and also 4 small round spongey discs that can be removed from the inside liner.I removed these for a custom fit. The helmet does however sit really high on the cheekbones,leaving more of your forehead exposed. This helps with the extra visibility when your in a tuck position.
Hope this helps guys
Hope this helps guys