I would think one of the issues that you will have with a jet is that the bottoms of 22' and up cats are not setup properly to feed a jet pump. Before I bought my 21' Daytona I spoke to the a couple of manufacturers about building a bigger jet and got the same answer. I'm sure with the help of a pro the bottom could be modified but by the time you do that you may have reduced any savings that the jet may have provided you in the first place
Gas Turbine...I've always thought that boat was too cool, the ultimate weed wacker if you will Do you have any pictures of the boat in the water at speed, I would love to see that.