Greg--I made the very same up grade on my Pro-17.
It will use up a lot more juice.It would have been nice to get one with a maximizer,or up-grade to 24 volt.
The factory wireing was too small (10 gauge).I had to re-wire with 6 gauge wire and 50 amp circuit breaker.
The foot pedal is alot taller than the M.K. I made a recess in my deck,and it makes it alot more comfortable in the long run.
This motor is practally unbreakable.Almost two years with no problems yet.The old M.k. is sitting in the basement all twisted and bent.
55 lbs is plenty for that boat.I have put my bro-in-law off the back deck,and into the drink twice already (whoops,sorry dude ; )
MAKE SURE YOU USE THE RIGHT SIZE WIREING.