Yamaha 200hp 3.3L or 250hp 3.3L ?

Good evening,I have to decide which of these motors to purchase.The specs are the same, difference in HP I suppose is due to difference in the injector pump.If I don't need top end but more concerned with just thrust(heavy loads) and being kind to the block by propping down.My question is why would I spend more for the 250,am I wasting my money they are basically the same motor.Any input would be appreciated thanks.

What kind of boat is this going on?

Thanks for replying,I'm replacing a 250 Saltwater Series engine on a 30 ft flat bottom aluminum boat.Empty it can scoot along at 30 or so(pretty good) under load of approx. an extra 5,000 lbs it can go maybe 12knots at 2,500 rpm( from experience and propping down as much as possible I don't push it under load as I will blow the block.It's kind of a compromise when I was experimenting with props.I'm hoping the 4 stroke and gear ratios on 200 or 250 will be a little easier on the block with this program with that said I did okay with the old 250 Saltwater Series,but what do you think 200 or 250 when considering this application or?