FWIW, what my regular mechanic (at one of the top independent garages in my city) said about the V-10 is that even on the later ones, the spark plugs have a tendency to break in half when removed, so I should either:
A) Steer clear of the V-10, or
B) If it's anywhere near 90,000 miles, ask the rental company to replace the spark plugs before I buy it, so that the person sitting there with half the plug in his hand isn't me. This is what I call the "new plug problem." The old one was just blowing the plug straight out of the head.
The unit I'm looking at had its plugs replaced at 66,000, currently has 90,000. Going to ask them to put in a new set, anyway. It'd take me a long time to take the current plugs up to 90,000 miles, I think, but you never know. I'd almost certainly never have to replace a new set. Even my nine year old car only has 65,000 miles on it :)
