I have been looking for a pair for a good while and this is the only good option I have found.
Details here: http://www.africanqueens.de/html/lc8_rallyekappa.html
Not bad for 1000 euros, except ypu then need to buy the custom headers:
bit of a power increase I think, but don't hit any rocks or you'll have a major restriction
Ohh, and there 2000 euros.
If anyone has any idea about tanks using stick exhausts I would love to here about them/ buy them immediately.
Hope this helps.
P.S. does anyone actually own a biek with these puppies on them, pics plz!!!