[Putershark]

In reality, I bet the only difference between the 2 engines is more than likely only ECU programming for I think that stroke, bore, and CID on the 2 engines is about the same

If anything you would pretty much only see the 15 horsepower difference in the bottom end (and the ability to swing a slightly larger prop), for prop slippage would come into play long before much of a top end speed loss between the 2 engines could be really found...