Anyone done it and do you suggest doing it? Just looking for a little more on the top end.

I wouldn't advise it. What you get on the top end will be negligible, and the negative impact on handling and torque out of the hole won't be a good thing. IMO, you will just spend a bunch of money switching over with little or no advantage.

I wouldn't do it. On a twin engine boat, I'd consider going from B3 to B1s. But a big single, no.

I have not done it, it is not a good idea for the reasons stated. Best to swap boats to a 271 if you want more on the top end of the speedometer.