Nissan

I went to buy a used car from advantage nissan. I asked if the car was ever hit or anything like that. They showed me a carfax copy and it came up clean. One of my friends is a bmw mechanic, and when he went to look at the car he told me all the parts that had been changed on the car. Then I took it to auto body just to make sure, and they told me the same thing. I went with a lawyer to get this resolved, but the contract that they made says that I cant bring them to court for anything, so now i'm stuck but they are loop holes. Also they sold me this bogus warranty that is void after 2 months and paid $2000 and the dealer said it would be for five years.