Just bought a decat pipe for my R53 S, any idea of what BHP gains im looking at? Will it fit strate onto my JCW Exhaust which i got of an 06 plate jcw? Cheers :)

Sorry for these answers, but it is better to know the truth ASAP !!

BHP gain = close to ZERO or even a DROP in BHP as the R53 likes a CAT of some sort or other. This has been proven on a number of cars.

It will not fit with your JCW exhaust or any other exhaust as you will need to change the manifold. The stock cat is welded into the stock manifold.

Question
Is your JCW exhaust just the twin back boxes or does it also have the central resonator box welded into it??

Cheers for the reply :)

Oh well, Best put it up for sale then! How much is it worth?

umm its got the central box too, i only put it on there because my backets on my standard exhaust snapped. It sounds much nicer with it mind.

As above really; it lost 5bhp and 5lbft when fitted to my car...

Worth ? No more than about £30 2nd hand BUT thats based on it being a Janspeed decat pipe...