I"ve been aboard two different Axiom 42's while on the trailers. One was the flat deck like the one on that sight, the other was a tall deck version (same hull) with a huge cabin.
The flat deck (race version I think they call it) had tripple big block engines (no sure of hp) and the tall deck had tripple diesels. In May, 1998 we had a freak tornado/wind storm in Grand Haven. The tall deck, which had an awsome paint job, was left tied to the wall in the Grand River in Grand Haven while the owners walked into town for dinner etc.... the storm came up REALLY fast and this boat banged against the steel curagated wall, fenders rendered useless by the over 4' swell coming in from Lake Michigan. It made the port side of the boat, from stem to stern, look like someone had taken a cheese grater to it. But, all the damage was above the waterline, so my friend and some guy who knew the owner (I recongized him) started the boat (push button start, no keys) and idled it to the other side of the river and beached it so it would suffer no more damage. I picked them up on the other side and brought them back to town. It was an ugly sight!!!
I've never seen either of these boats on plane though..... always seem to be tied up or on the trailer.