I haven't raced Karts since I was about 18, but most of it depends on just how competitive you want to be. Your best bet would be to get with someone who still races down there and find out what classes are popular, it won't be much fun to only be racing a few people every week. As long as the chassis is in good shape, it should be pretty obvious how its been treated. The engine will just be crap shoot in my opinion.