If you go with a back rest for the kappa case, your passenger space gets allot smaller. We canít even use the back rest I bought, because my wife's coat has padding in the front and rear (she is, btw, medium size, but athletic). Works out thought, because the spine armor serves the purpose of the backrest when against the Kappa. She has absolutely no complaints.
That brings up another point... I don't see how you can use the corbin seat back-rest, with soooo little room. The pasanger would have to be some 5'3", <100# to to fit?
blue 2004 1000