if you keep it at stock boost and don't allow boost for extended periods of time (ie always floored or very high speeds) you will be fine. though you will notice a difference using one.
what they do is they cool down the air charge (because pressure creates heat) so you can (A) cram more air molecules (more oxygen) and thus more power and (B) the more core function as already stated is to cool intake temps so your combustion temps will become lower and thus you can push your engine a bit harder.
Water to air systems are great for lower power setup ups and drag racing (probably drifting as well). Since an air to air intercooler needs air to come across it, it works better the faster (more air) passes though it. a water to air intercooler isn't effected by that nearly as much (though speed still helps) if you wanted say no more that 450 hp then it would be a great. it would allow great cooling off the line (witch air to air have trouble with right away) and still have good performance at high speeds, IT also would be harder to heat soak if the setup was good.....though from what i see the air air ones will preform better at higher speeds...which in most cases is where you are really going to need it anyway. i have seen some setups and plans for both but that seems expensive and for the gain you would theoretically feel...pointless.