The twin spark down pipe from the engine is 1mm larger than the earlier model!
Notwithstanding... I fitted a pre 2004 Remus to my '04 Dakar
I carefully measured, and cut off the front of the Remus with welded on clamp, because it wouldn't slide over the original front pipe, so that when in situ it was a 'but fit' to the orginal header pipe... the two pipes are exactly the same diameter. Short piece of stainless tube inserted inside each to act as a sleeve, then the original clamp fitted over the joint. (needs a bit of padding out to make it a tight clamp type of fit)... hope you know what I mean!
Now done over 40,000 miles with this mod, no probs
Same as Micky (who advised me it could be done ). I have a set of 03 Remus cans fitted to my 05 Dakar. For the sleeve I went to a local tube manufacturer and had them swage out a 75mm long piece of s/s tube to fit snugly into both header and tail pipes.