Air/water has a fluid encased intercooler that cools the charge. The fluid is then pumped to and cooled by a heat exchanger up front of the radiator. What you're referring to with the ac is a Killer Chiller that uses the ac system to cool the fluid instead of just a radient heat exchanger.
The pipes question depends on underhood temps. If the temps underhood are higher than boost temps, then the aluminum pipes would absorb heat. If the boost temps are higher, then the pipes would radiate heat.