I have a SJ chamber in my X2. Heated up the tank and pushed it in about 1". I do have a Kawi 750 motor w/ a westcoast 650 manifold and Kawi A-pipe, and the chamber doesn't line up correctly with the head pipe, so it's not quite all apples. It does work however.
I do have to admit I am not pleased with it. I never have been. I was happiest when I had my other hull with a SJ waterbox going out the right back.
There is definitely a lot of compromise with a X2. I just hate seeing good pipes dented. I know it kills the tuning. I figure one might as well have a bad pipe that fits good than a good pipe that's been turned into a bad pipe that fit so-so.
Not sure if you ever googled 701 X2 but there are some good examples out there to follow now.
Only linking pictures of fully assembled skis. The ones that don't have fuel tanks in wont help.
This one looks like a Kawi motor