I was told that its the manifold and cat that make the difference with regard to bhp.
The rest of the system, although it has some effect, less important.
If the rest of the system is ok, save your self some money…..
Cain said at Blenheim that changing the pipe from the manifold to the silencer is a useful change (I have a side exit) and quite a cheap fix as that removes a constriction.
