The 2.5 liter Mercury 150HP ProXS would be OK on a 22 foot CCP, but the boat really performs best with 200-250 HP. Unless you can get a great deal, don't go for the 175 ProXS, as it is the same engine as the 150 with different decals and a higher price. That motor would push a 22 foot CCP pretty well when propped correctly - probably a 19 pitch 4-blade would work pretty well for that setup. This 2.5 liter was sold in the past pushing a rating of up to 200HP, so it's likely to make more than the listed 150-175HP.
I just switched my 22-2 CCP from the old Mercury 200 Black Max (2.4 liter) to a new 200 Optimax (3.0 liter), and am amazed at the difference! The 3 liter is a torque monster! As the old saying goes, "there's no replacement for displacement." Check the prices carefully - some dealers are willing to discount these motors - especially at the end of the model year.
I hope this helps - please feel free to post more questions if you have them!
