Can i return this car?

First, get the smog test. Then, you can try to cancel the deal. However, look over your paperwork. The standard contract probably recites that the written contract comprehends the whole contract and that you are not relying on any oral representations. If you think you can prove fraud you can sue for the difference in the value of 99 Miata that will p and one that won't. Whether the judge or jury will believe you or find it to be fraud is another question. If the dealer got is ped, then it wasn't fraud and you are limited to breach of contract and, as noted above, in most cases oral representations are not included in the contract.