I had one of the first set's of 300's that were built , put over 100 hrs on them , never had a bad moment, they were great power for a 6500lb boat and got good fuel burn at 4-4500rpm, about 2mpg, after that it droped off a little, but the engines were great , I did not like the cost of oil changes to keep them in warrenty but that just goes with the teritory ! 6yr warrenty from Merc was tough to pass on , they are heavy, make sure ya get the CG correct on your hull when they are set up , all in all they are a very good package , good luck .
RHC