If you want to go fast- 2-stroke
I'm bumpin 80 in my SHO. That's fast enough for me. As I mentioned before, you dont see those that have ran both going back to a 2. Go run them both and then decide. You really cant go wrong either way. I do think the PRO XS is a little faster on top end but there is no comparison on hole shot and mid range power.
My "slow" 4 banger did 79.8 mph Saturday, 50 gal of fuel , loaded down heavy tourney load, 2 GROWN men, livewells full!
light load mid 80's , and thats fast enough for me!!