You will need a downpipe, either decat or race cat, ideally 3" and a pipe to mate to your 2.75" milltek cat back... or you could get part number msau343? from milltek which is the pipe from a 3" down pipe to a milltek cat back(think about £40) and just get the downpipe fabricated... then you can go stage 2 :) (Not Revo Stage2 on an Edition - you need more than a downpipe!)