Same as buying any used bike, just look it over well for signs of abuse. The big motor is a real work of art, with the stock exhaust it's the best sounding bike ever, imo. There is a yahoo vmax owners group you can join, I think it's linked at
www.v-max.com.
Common mods to the max, not counting all the possible exhaust variations... new fan switch from local auto parts store to make the radiator fan kick on at a lower temp. Frame brace, on a hard dyno run the frame flex is visible (that's how strong the motor is). Fork brace to cure the high speed cornering head shake some max's show (mine doesn't). I believe the frame brace is the most expensive and it's under $200. I think. You can also do what is called the "Furbur Fix" by rearranging the steering head nuts and washers to eliminate the shake. That can be explained with a google search.
two sites to help you out, if you haven't seen them already...
http://vmaxoutlaw.com/ This history page is neat, tells you of the changes over time. 93 on has bigger forks, 96 on has the spin-on oil filter, etc.
http://rmsportmax.com/gateway.html I think this is John Furbur's own site, plenty of stuff for the max there, including used bikes. He's in PA.
The handling issues are a bit overblown, imo. I race through corners and scrape the pegs just as I did on my 95 Magna, it just takes some getting used to the feel of the bike's weight. When you come up out of a corner and hit the throttle hard, better hang on tight. The v-boost kicking in is like getting a hard push in the middle of already hard acceleration.
This is my 97 sitting next to my recently acquired Kawi ZRX...
http://img.photobucket.com/albums/v215/ ... 07f5cf.jpg
http://img.photobucket.com/albums/v215/ ... 4365a4.jpg
Hope this helps... max is a truly awesome machine, old tech or not. It still kicks but and draws a lot of attention.