I have run a couple CC35's with 450C. It is a heavy boat for its size and tended to stand bow way high when getting up. Enough that you could not see over the bow. Took 2300-2400 to get to a decent speed and running angle, and that is hard on the engines. The one I did serious work on had a leaky head gasket and cracks in the head. Exhaust mixers were factory and too low to guarantee no water in the turbo.
Seemed like well built boats, but when running it I always felt where the heck is all that horsepower going??? I kinda doubt it is only 25k lbs. Felt heavier to me.
In comparison I have a Carolina style cold molded 38 with ONE 450C that planes at 1800rpm and tops out at 30kts.
On the plus side, the weight and deep vee will make it a beast in snotty seas.
The 450C and 480CE seem to have issues with valve seats if run hard. The QSC 540 has a completely different head with 4 valves vs 2, and does not seem to have any such problems.