vectra_Mike said:
After reading that How 2 the question ahs to be asked... why did vauxhall even bother with it... it looks like its just gonna restrict the hell out of the exhaust system :/
Same as they do with a lot of stuff, trying to reduce noise/emissions, restrict output etc.
IIRC, the Z16XE engine fitted into the MK4 Astra was heavily resitrcted by Vauxhall, as it gave more power than the 1.8 engine!