Assuming 2013 model year, same frame (E5), same fork (carbon/alu. steerer), same wheels. Both have mounts for fenders, racks (front as well as rear, iirc).
Difference is in the drivetrain; significantly better (and will be easier to source replacement parts as needed) on the Comp. Would be worth it to me, provided there's not too much price difference in Japan.
By the way, tire clearance on the current Sirrus is pretty good; you should easily be able to use anything up to 35 width without any issue. Given the riding use/conditions you describe in your other thread, I can't imagine why you'd want anything "wider".
Also by the way, I wouldn't let discs be a deciding factor (e.g. between Sirrus and Bad Boy) -- again, given where you ride/what you use the bike for. I use a 2010 Sirrus Comp for 3+ season commuting, and long weekend road rides here in Southwestern Ontario; we can have harsh weather conditions, and we do have very poor roads, heavy traffic, etc. I've never felt the v-brakes to be compromised in relation to my other, disc-equipped bike that I used for the same purposes 2005-2010.