I heard Mercury had some crazy low sale prices on outboards. Did you consider one of those?
Another thing to consider is the weight of both motors. I'd imagine the optimax weighs more than the etec. What's wrong with the current controls? Are they not compatible with the Mercury? Did you consider have a new skeg welded on?
I have been looking at the 90hp and 115hp etec's and can afford one in the sense that I could buy one without putting myself in the poorhouse. However i do feel that putting a $10,000 motor on a $3000 hull is sorta rediculous, even if it is an aquasport Thanks for any insight, my wife just says do whatever I want.....which is nice but doesn't help me make this decision.