This is true and even with a turbo the cooler the air starts out the cooler it will stay. I think the main idea is that cooler air is more dense and therefor contains more oxygen. But I do think there is a big misconception out there that as long as there is a pipe and a big filter it is a cold air intake. But the truth is, if it is sucking hot air from the engine bay it is not doing much good and is not a cai.

you're correct about pulling air from fender, kinda... you wanna pull the air from a closed area, as low as possible. However, too low could suck up water if you drive through a deep puddle/flood. Afterall, hot air rises, the cooler air is down low. You can also wrap the intake pipe as well to keep thermal temperatures from negating the temperature of the air being pulled through the cold air intake. GL w/ your supra... my NA needs a 7mge rebuild atm :\