Thanks Warren. The S52B32US motor requires 4 sensors: 2 precat and 2 postcat. This is due to the truly independent dual exhaust on the M3. I'm going 2 into 1 before the cat, hence my question on being able to get away with a single sensor after the cat. BMWs may not like generic cats, but i feel confident that a generic cat is going to be miles ahead of running no cat at all which is how the car is currently setup. If the generic can't get the job done, I'll consider getting an OEM M3 setup and cutting the cats out to fit my car. |