for what is worth... i would try a pair of 150 yamaha hpdi's or mabet the new bombardier e-tech 150's i did a 23 center console that had t/115's repowered it with 150 yamaha hpdi's top speed was in the 40kt range w/t-top and full load of fuel npt too shabby fuel economy was very good sd well. i would not put 200's on that rig you will rarely use that top end the extra price for the engines in my opinion is not worth it. if you want a race boat buy an apache w/kieth eckert engines. your mechanic sounds like he's giving you great advise tellimg you to forget the 250's