Yes, they call it a repower . . . Bummer, but pretty much true. Somebody had a turbo kit on eBay recently, but the consensus here is "fuhget about it" . . .
Well, with Honda Civic's, if you replace the wiper blades with yellow ones, they appear to make the civics's go faster.... sooooooo why not paint the rocker cover yellow or the pulleys.
j/k
Keep it well maintained, tuned and running, that is about your best performance upgrade. As the others have mentioned, if it is really a tired out motor, then a repower might be in order.
I'm thinking about putting a coffee can muffler on mine. That's what they do with all the little cars around here to make 'em fast anyway. Only problem is I can't exactly figure out how to with the exhaust through the prop.....
The experience I've had with my 3.0 so far is it's not fast, but with tune-ups and oil changes it is rock solid and reliable.
It takes a LOT more power to go a little faster in the water. The 3.0's are built pretty good already for their size and hopping one up will cost you more than you will see in performance gains.
3.0's get pretty good gas mileage too. If you don't like gas pump shock, stay with the 3.0.
That would be another reason why I have a 3.0L in my boat, gas consumption. I already have a 4.3L in my GMC Sonoma and I know what the consumpton is like as a daily driver.
Im still trying to figure out how big my tank is and how far I can go on XX number of litres of fuel.