bit late i know, but, i have done heaps of reading on this, and have played with a few setups also.
air to air, good and effective when done right, hard to get piping to front, past hot areas have to cut holes and make room and the list goes on.
water to air.
water is like 8 times more effective as a heat exchange than air, so much less surface area to do the same job, thus being much smaller, seen the water uses a remote cooler to the intercooler itself, so the piping can be very short. the only off side to water cooling, is the weight, you have the intercooler and the heat exchange, but the most weight comes from the water reserve.
they are very popular in drag setups, as air to air requires decent air flow to do a good job. where as water stays cooler much longer. very good in a drag set up as they usually use dry ice and can cool the intake to very very low temps.