For 600 dollers I would by the warranty. Iam getting a ranger soon and have been talked in to a 225 vmax. If you don't think the vamx is good check this out. I pmed glen about his vmax and this I what I got back.
1. Is the hdpi really that good? Yes. I love it.
2. I know that the gas suffers a little but how munch? Suffers? By who's standards? I can go 400-500 miles on a tank, easy.
3. Do I really need the trandsome saver like you have? Yes. It comes with the boat. I'd even say it's mandatory regardless of Merc or Yamaha. A 225 weighs around 500 pounds. It would be insane not to use it. If you lose it, however, my suggestion is to order a new one through the Ranger dealer. It's tough finding a replacement long enough.
4. Whats the top speed with that my buddy is looking at 519 vx? Top speed really depends on boat setup and load. I think the 80mph you experienced is beyond expectations, though. The boat had to be empty to get that speed. Fully loaded, full livewells, a buddy, and at least half a tank of gas will bring that down in the low 70's. Keep in mind each boat has it's own "personality" when it comes to proper setup. So experimentation is the key. What works for one guy usually doesn't work as well with another guy using the exact same boat/motor combo.
5. I don't know were you live but how is it starting in cold weather? That's an interesting question. I have had some starting issues when the temp dips below 45 (excessive cranking to get it started). The Yamaha mechanics worked it over this spring and gave it some new parts. Of course it hasn't been cold enough to try it out yet, so I can't say they fixed it yet. That said, I've still been able to start it in 30-degree temps. I expect I won't have any issues this winter.