My edelbrock carb uses significantly less fuel than the holley that was originally on there. Performance seems comparable.
If you're looking to only wakeboard, repitching the prop will save you a lot of fuel but will cut your maximum speed dramatically. It's a trade-off that you would have to make and it sounds like it would be worthwhile.
The boat shouldn't be any harder to start than a fuel-injected model. Mine starts just as easy and quickly as all of my friends newer boats.... unless it floods which will leave me sitting for 10 minutes trying to patiently allow the fuel to evaporate. Obviously, FI boats don't have this problem.
Former owner of a 1987 Supra Saltare. Current owner of a Malibu 23LSV.