How many hours on the engine? Are you the original owner or do you at least know the history of the boat?
If it was running fine before and everything else checks out, perhaps a really light hone job on the cylinder bores and new set of rings and put it back together. I wouldn't touch much else.
Do the crank journals and con rod bearing shells look OK?
2005 X2, Viper Red, MCX, OJ TZ-X5 prop, PPass, rear 750 sacs, KBS, IBS, Bennett Wake Plate, custom wake shaper
(previous) 2001 X5, 1991 TriStar 190