Mingster, on the CAT replacement tube, what other modifications to the ECU are required? Or are there any at all. Will the car perform as stock at idle etc.? I know this was covered once before somewhere but I can't find it.

 

Neuspeed exhaust doesn't come with the "test" tube (cat replacement), Spoon's exhaust does.

As for the check engine light, I know Spoon ECU can take care of that, but I don't know of others.