Hi monkey, if it any help i would highly recommend speakin to these guys...sorted my k6 out a dream!
www.mtcexhausts.co.uk they done all the work in about 30 mins, and made me a great cuppa! £150 got me a single outlet oval stainless with removable baffles, fitted! it now actually sounds like a v-twin and given me about another 5 or 6 horses...really can't say enuff about martin & his crew. worth a call