Neither are the big TT Schiadas though and there are some "stoopid" fast turbo Schiadas here on the west coast. If youve ever watched a 22-24 ft schiada pull a skiier to Catalina youd be amazed.
As for the australian speed skier boats
Ive seen these and actually more than a few are 1400+ HP Twin turbos pushing #6's but more often v drives.
Nothing Id want out on 5 footers though.