When considering junking the header/manifold system on a R12ST to be rid of the cat and finding 0.5bhp

, can anyone advise about what will fit? There is a firm selling header pipes for the GS on ebay. No one seems to sell pipes for anything other than the GS or RT. The cost of a Remus system is OTT and the 'home made' headers from Sandy Bike Spares are a bargain in comparison. Question is, anyone know if the underside bits will fit? Obviously the cylinder end is going to but it's the mounting bits hidden from view and then the connections to my Beowulf pipe that I'm thinking about. Any half decent suggestions out there? Thanks!
ebay ref: BMW R 1200 GS R1200GS ADVENTURE EXHAUST HEADER DOWNPIPES DOWN PIPE COLLECTOR. ID number: 151065429084