Re: Motor size for 2008 Pro Team 170 Tracker
The 2010 Pro Team 170 has a max HP rating of 50. I don't think they changed anything on them in the last 2 years, but your boat would have a placard on it stating the max HP. You could probably put a 60 on it and drive it without incident, but I'm always the type to stay within the stated limits for peace of mind. I'd go no larger than a 50 myself.
On changing out the motors: if you change brands of motors you'll definitely need to swap out the control box, but if purchasing a new motor it'll typically include the new controls. As to difficulty of swapping them out - no clue. I've seen people swap old tiller steers with no power trim and that was a pretty simple process, but I'm not sure on the difficulty of a remote steer with power tilt.