Mikey, with any boat you get, do your self a favor, if your going to venture into the ocean, or Gulf for that matter, invest into a Epirb, so if any storms do kick up, and shi* hits the fan, the coast guard will receive the distress signal.
All though I dis-agree with the above post about the I/O, as I've had plenty of I/O's from 22' upto 34' inboards, I don't see any problems with a I/O, as long as it's fresh water cooled, but most important, is power to weight ratio with a I/O
Next you have consider weight. Can the boat get onto plane with 4 divers, all their gear, and tanks, You would be surprised how fast all that equipment makes the boat heavy.
Also you have to watch not to exceed the boats MAX weight capacity, while carrying all your divers, and gear etc.
I dove my own 24' Cabin cruisers, and had issues with the boat being under powered, being it was a I/O, and carrying a 3 divers
I also had several center consoles, with outboards, and the outboards tend to jump the boat right outta the water more quickly, and can stay on plan.
Why does power to weight ratio count so much you may ask?
Think of a calm day, boat full of divers and gear, your out diving for the day, and a storm kicks up, and your heading back in from 10 miles off shore, and suddenly your in 4'-6' seas with a loaded down boat.
You'll need the power to keep the boat pointed in the right direction, and to not get caught from an incoming sea from behind
I been diving off my own boats for the past 5 years, until about a year ago when we sold the boat and bought a motorcycle.
Me personally I think Sea Ray makes a great hull, Little over priced because of the name, but being it's a 22' with a I/O, I'm not sure if it would pull the weight needed for several people to dive off of.
If your going to use it every once in a while for a dive boat, but mostly use it for family outings and a cruiser on the weekends, you might be " OK ", but if your going to use it all the time for diving, I would look at another boat, maybe a 23' Center Console with a outboard, nice dive platform on one side, with a real dive ladder mounted to it.
Good luck, and EPIRB !