Keep checking on Ebay. Those tanks come up probably monthly.
It fits like a glove on the SXC,
Komfort seat, you can't believe how much of a difference it makes.
I've had mine now for almost 3 years, a little dished (broken down foam)
right in front of the neck of the gas tank, but still very comfy.
Have a buddy who did the exact same swap, borrowed my 18L tank to see if it fits, now got almost 5 k miles on his SXC, comutes 30 - 40 miles a day, loves it!