Nah, I don't think the bigger heads offer any performance advantage really.
Perhaps to a small extent, but the overly huge heads especially tend to 'mask' an overly lean mixture. This is true for those who tune by temp. You may be getting a reading 50deg lower than you're used to; so you lean and lean it out until temps rise ... but when doing that you're forgetting that there is less and less lubrication flowing through your motor!
Have to be careful with aftermarket heads ... can kill your engine without knowing it
I would think Novarossi and the like know what they're doing .. and include the size of head they do for a reason.