Definately not too much horsepower for that boat. I know of at least one with 300X's, he runs right around 90 with it.
The 2.5's are awesome motor's but you can't get a whole lot of hours on them without tearing them down. Plus you will be going through a lot of gas on a boat that size with twins, manually adding oil is a pain.
A pair of 300XS's would be a better alternative.