Please, for the love of Games, don't bring up Xtasy Mod. There's been too much speculation to recommend it to anyone.
It doesn't have an official website. The "official" site that it came from was not for FPSC, someone just grabbed another Mod and prepped it to be used in FPSC. They posted it up here, feelings got hurt, big mess.... don't use it.
But since I know how people act here, I know you're still wondering how nice it'd be, so I'll lay it out for you:
1) There's no water. There's only "Bloom" and "Motion Blur"... and some other effects that never seemed to work right.
2) The Bloom makes EVERYTHING bloomy. This includes your HUD overlay and even debug text at the bottom. (Not cool)
3) The Motion Blur only seems to react to mouse movement. Running really fast didn't seem to trigger it, nor did crouching or falling. It was also blurred in a very low-grade fashion, nothing realistic about it at all. Just like Bloom, this also effected everything on screen, including your HUD overlay. Not cool.
4) I have a monster computer. I put the Mod on in a map running at 286 fps (uncapped it for testing), but as soon as I turned the Mod on the framerate dropped to around 16 fps. Not cool.
5) Even if it did work perfectly, this Mod is not like the other Mods, it must be ACTIVATED, meaning your built game will NOT have it in there unless the person playing presses F12........ Not cool.
There you have it. 5 good reasons not to use Xtasy Mod. Look, this is an external DLL hack that's commonly used to implement cool stuff into commercial games that you don't have the source code to. It's a horrid way to put effects into a game if you're DEVELOPING one. All in all, it's just a cheap hack, don't waste your time on it. Grab a programmer from somewhere, they're a dime a dozen, and pay them to make a REAL Mod for you.
The one and only,