I wouldn't bother with that place nr market rasen, they made me a 2 box system for an Ibiza gti for £360! And it knocked, banged, didn't ft properly and I had to "make do" with a tailpipe that wasn't my 1st choice because they had a very limited stock of tailpipes in!
Theres always dynaflow in Lincoln, bloke called Fin does them, his work is amazing and his prices are a lot more reasonable than powerflow!