I think the Aqua Sensation has a hot and cold water feed from tanks, if so you can replace it with the AS2000XT. The showers are different sizes so you may need to move pipes or repair some of the wall but you will see that when you replace them. The triton websites has the user instructions for the showers and these have schematics so you can check before you buy.
Good luck.
Paul M
May 2009