The xl works great for me. Just make sure whichever one you get you do the install in the proper order. First install the ring on the gas cap. Then attach the bag ring on it without the bag, then take the bag and place it on the mount. This allows you to slide the bag back and forth so you can choose the mounting location that works for you. Check your bar clearance at full left and right before you start drilling any holes. The xl is a roomy bag it may be too large for some people taste. I like to carry a lot with me when I ride as you can see from the post that was linked in the previous reply.
Great quality bag though IMHO. Very easy for me at the fuel pump. I have to fuel up about every other day so easy on and off is key!
