Honestly, I really do wish I had the 75 on mine. The 60 is great, but the holeshot is sluggish. She goes 35MPH with a full load and a partner. with just myself I can get her around 40-41 pending conditions.
I am not sure if you will notice much of a difference with the 50-60 motor. but do get the 4 stroke! its an awesome motor!
Goodluck, its a great boat!