I would pass on this deal. I would be wary about the the previous owners. I stress owners. The car is roughly 4-5 years old and has had two previous owners. The car has also been poorly modded based on your description above. Who knows what has been added or removed from that engine? I know you talked to the previous owner who claims the car is fine but I would still pass. There are a lot of great cars available on this site and others. I would hold out and buy a 1 owner car.