I would just check for play in the bearings, if it is running smooth. A-arm scratches can tell somewhat what kind of wear it has unless it has been repainted. The ex's are pretty solid so there reall isn'e anything to look for weak spot wise.

I also wouldn't buy anything with engine work done to, that usually means it has been ran hard.

But evertything I stated above can be disregarded if you find one dirt cheap.