And you is going to slam it, ey? lol...
I think you could get your map tweaked to slightly over fuel the engine but I'd be concerned about the damage this sort of kit will do to your cat... Unless you don't run one then you should be OK.
I'd love to be all sensible and say don't bother, but the sound of an exhaust popping as you slow down is appealing. Whether I could live with it all the time though...