It's great for making room around the headers. If you don't want to go through the hassle of removing ALL the equipment, just get a shorter belt, like 71-73 inches. Then cap off the thermactor pipe and remove all the hoses. It's not a big deal to leave the pump on since it weighs nil.
There is no really difference in power, you might get 5-7 hp out of it. The only advantage was more room to work with in the engine compartment. So if you do have emissions I would just leave it on. But if not make sure you block off the pipe on the H-pipe for smog.
sure makes the engine compartment look better, not sure if you're going to gain much from it, but if you have to pass emissions checks where you live make sure you keep everything you take off because you're gonna need it.