Took my 2001 xkr to MIJ performance in Birmingham and they done a really good job. I had sports cats and stainless steel cat backs, X-pipe and Porsche tips. Looks really nice, sounds great too and I get no drone just sweet symphony from the engine with the s/c and exhaust but did cost me £1300 but only because the cats on both side are a bugger to sort out. Definitely worth looking into.
Check mine out on YouTube and search MatiousDaViking for more info