How effective is the XPS mod?
The XPS modification does allow water guns to fire when upside down, but it is fairly useless in terms of creating constant pressure. As long as you want decent pressure, the majority of that pressure will come from compressed air. The XPS modification will simply take up space in an attempt to change the water guns entire pressure system. It is more useful to buy or build another water gun or to replace your water guns pressure chamber entirely.
