The XS waterbox used to have a 90 at the top so they could use the same design for front exhaust also. With the old design, you had to cut your expensive long hose to install it. Also the long outlet height was a problem to fit in some of the newer hull designs.
JetManiac encouraged them to change the design so now it fits more like stock waterbox and no cutting of long hose is required. It will fit in more a/m hulls as well.
XS still makes them, but supply is always an issue. We always have them on order, but always a wait.