Hi mate, I have the TP164 fitted to my corsa and passed the cat emmissions test after a bit of playing about with the managment. I did fit a high flow racing cat for the test. The first time I went in the car failed, but that was due to lambda being too high (no lambda sensor, I could never get it to work with the managment). However emmissions were zero at idle and fast idle. I put a bit more fuel inot the map at fast idle speed to bring the lambda up and the car passed the second time OK. I have heard that hot cams can give you problems, but with standard cams you should be fine.