Good comments all. Not to bore you with details, and publish a novel here, but...
I bought our existing Carver largely because of cabin room and height. I'm 6'5" and there are precious few boats that work for me, and my budget. I've loved our Montego this year, but after living with it for a season, of course, there are still a few areas of compromise.
Firstly, a larger bed/berth in the Master stateroom would be great. Something long enough!

I thought ours would be okay, but really...it isn't!
Our existing gunwales are fairly high...an easier entry to the cockpit from the platform without having to stand on/step over a transom seat would also be nice. A little more cockpit room always a plus.
A slightly larger aft with standing room would give company more changing & dressing room.
Full sized fridge a plus.
We usually anchor out each weekend, but are less than 20 miles from a huge selection of anchorages. The gas motors don't bother me. My current 454's will keep us on plane at 3000 rpm quite comfortably, without 4barrels being open. Our Montego is listed at 13,000lbs, easily we have another 1-2000lbs aboard, between all the normal crap, water, fuel, beer/booze etc. The specs say 16,000lbs for the 380, I suspect we will still be fine. I was quite pleased with our fuel economy this year, actually.
I do agree re: flybridge style boats, they certainly give more entertaining space, but can't bring myself to consider them, I just don't care for the styling. I do however love the 380 Santego for all the mentioned advantages, but they don't have another cabin, and the Admiral won't consider one without! A double cabin Santego is really rare, from what I'm aware of, and it compromises the size of the master stateroom and berth...back to that. (Would love to have walk-thru doors from the cockpit tho.)
Definitely, a full ER inspection will be in order. The boat is in freshwater, I suspect it may be closed cooling. I think hours are 900-ish. I took mine with 1050 on them and they ran great.