In 20 foot walkaround cabin boats, it doesn't get any better. No 20 foot boat exists that gives so much in so small of a package. In sea going usage (ocean), minimum HP is 150 V6 2 stroke if the model 205 is outboard, if I/O, ignore.
Have what ever you eye up, surveyed by a surveyor who has done Gradys before, it is very important to have Grady survey experience, be sure to interview beforehand.
Good luck.