SXC 18l + comfort seat
I added the 18l tank and confort seat last year and have been enjoying the benefits. The tank is 5.5 gallons + (20-21l) despite the 18l label. The seat turns the bike into an multiple day traveler even for a candy ass. The only downside is the stock suspension is a bit overwhelmed by the extra weight. Takes 5 minutes to swap back to the stock trail setup. As a side note, I had to modify the comfort seat to fit the tank on my 04 SXC, 10 minute DIY job.
Cogito ergo sum