I agree with the others that say to by private sale so you can talk to the owner about the car's history. My best advice would be to discretely ask the seller if he is on EvoM and get his username if he is. Then read his post history. You can find out a lot about an Evo by reading the owner's previous posts.

 

And while you're at it get their MySpace ID so you can peep 'em on MySpace too

No but really, that's a brilliant idea and I wish more people would think of it and do it, it would've made selling mine A LOT easier and made it very hard for a lot of people I know to sell theirs (especially people lying to buyers about the P0300 code)