A proper watercooling setup will give you better temps, that's a given. But, unless you want to want to expand it to also cool your GPU, the difference isn't big enough to make it worth it.
Please excuse my bad English.
Currently gaming on a PC with an i5-4670k@stock (for now), 16Gb RAM 1600 MHz and a GTX 1070
Steam / Live / NNID : jonxiquet Add me if you want, but I'm a single player gamer.