It all depends on how bad it is hurt. If you just scratched up cylinder then you can probably fix it with minimal work.
I'm fixing my buddy's 2.5 200 EFI merc that he blew up and it's basically just smeared the piston up & down the cylinder wall... I still have a bit more aluminum to remove but so far the cylinder wall is in great shape!
As far as modifying the motor, just cut the heads a bit to raise the compression & find a set of good reeds & rubber coated cages. That will pep it a up a bit and let it breath a little more.
Russ
