In Europe, you can run both P1 classes but I am not certain one can be really competitive with a diesel in either class as its a strictly HP/WT formula and there goes any advantages of either.
Hustler, Sunseeker, Buzzi and some others try to run in the P1 classes. In Supersport the Hustler is fairly competitive, near the front and lead a race, but in Evolution, the gas engines run away from the diesels. I think King of Shaves won by 4-5 minutes over second place and that might not have been a diesel powered boat even.
The boats are typically over weight for the rules just because they have a pair of diesels.