I'm looking to buy a 1998 A4 and the guy said the motor is swapped from an 04 Passat. He said its flashed and tuned on 18 pounds with a bigport swap done to it. Is there any way to look at the motor and find out if everything is true or even if its possible? He doesn't have receipts for anything, just stating he bought it from a mechanic who did all that. Please help.