How long does that extend the warranty? It sounds really expensive to me. In 500+ hours and 6 seasons on my X-15, I've had to replace a fuel pump. That's it. I'd say no.
That being said, I'd shop around. I have bought all of our stuff from a mixture of boat shows, mail order and the dealer. I'm all about the deal.
Good luck with the boat - I'm sure you'll love it.
2007 X-15 - Sadly sold