Sorry , having read your post again I notice you say the pipes cost you £850 so it sounds like an Asymetric system you have bought , not sure exactly how much extra power you should get from that , it is definitley a lot lighter than standard (about half the weight
) ans sound much better though.
Full systems are supposed to increase power by approx 8% , hopefully someone else will be able to tell you if the Asymetric system gives as much or not
