I belive X-star's have a cooler under the middle cushion, which would mean that would not work. Corey is right, the Fly High X-star kit use two long, wide, flatter bags that go under each side... and connect in the middle via tubing to each bag.
It will fit in the old XStar / X2 bow. There is a specific X2 bow sac from Fly High that will give you 40 more pounds but it is more expensive than the Fly High Integrated Bow Sac.
yeah thats lame because I'm going to be riding behind an 06' X Star part of the week and a 07 Moomba LSV the rest so I wanted a bow sac that would work well for both and get me at least 650 pounds any other suggestions? I was thinking about just getting the 1000 pound bow filler but I didn't really want to take up the bow
The fly high open bow bag would be sick. I have used that in the Malibu VLX and a 21' Supra. If you don't need the room in the bow it will be perfect. You can also just put a Fat Sac up there. The Fat Sac will fit in both bows and give you 750lbs.