When it comes to buying a Quadzilla, all I can say is just go for it!

I am super happy with mine I bought a 88 just to avoid some of the bigger issues.

That said it is a great engine and I like it best of my 3 two stroke quads, Mine was already mostly restored but mostly back to original more or less, and I again went over some of the listed flaws, but it is at least worth it.

Personally I love the power of the 500 but hated the Zilla chassis.Too bulky for me,much prefer a hybrid but everyone is different.I sold my Zilla for that reason...As far a trouble areas I agree with what others have said and they seem to need more work than most to stay reliable...That said when running well they are a blast.