What is your objective?
In general, I think custom water cooling is good only if you are a hobbyist and like fiddling around with that sort of thing.
Haswell overclocks nicely until voltage gets high. Then heat builds up exponentially so each incremental multiplier takes much more cooling. At some point, no amount of cooling short of LN2 does any good.
How high does your OC need to be?
If your objective is gaming, spend the funds first on a better graphics configuration.
If your objective is rendering or other such app, spend the money on a 4770K or a haswell-E
If functionality is not an objective and you just want to experiment, then go for it.