The TT style exhaust you are on about,You do not cut the bumper the exhaust is a direct replacement for the original from the KAT back,I had this exhaust on trial before production and liked it,I did not have it on the Dyno so i have no figures but it did feel better .
My only complaint with the system was that it was too quiet
and so you can now buy it as a one or two silencer system.
