Doesn't work like that I'm afraid, if you're familiar with the energy conservation principles you'll know exactly why
That heat has to go somewhere, and unless you mount that rad externally, that somewhere is your room
If you stick to SP120QEs, even in push-pull, you won't be able to hear the fans over background noise. If your computer is the only thing making noise - then sure, they'll stand out without a fan resistor. Don't forget though that until you start pushing some air through the AMS rads, they don't stand out that much from standard 360x60, so you're probably better off getting some NF-F12s in push. I think they're pretty much built for that kind of rad anyway. I heard that they've released a black version as well, so if you hate the colour scheme, you're in luck

, though I think that stainless and copper on cream and beige would be better than just black on cream and beige.
The F12s are a bit louder than the QEs, however they push more air at the higher noise levels, and you've always got the option to run them at PWM from the motherboard using the included fan splitters, and they get quieter if you stick the included fan resistors on as well.
I find about 800 rpm to be a good compromise of silent running with decent airflow, the LNAs (resistors) take them down from 1500 to 1200 rpm, which makes little difference with a widely spaced rad such as my G-Changer, or even the Monstas, however you will see a greater benefit in terms of the static pressure it will generate to push through the dense AMS fins.
They run silent up to about 850 rpm, then they're audible up to about 1050 if there's nothing else making noise in the room, up to 1200 you start to hear them and past that to 1500 they're hard to avoid unless you're watching something, listening to music, gaming, etc. I find they do the job at 800 in winter times (up to 20*C room), but you'll probably need to have them at about 950-1000. I'd just run them off the CPU header on the motherboard, during testing, stick them on a constant speed to evaluate performance, and if they do the job in the silent range - might as well set them to a constant speed, if not - a fan profile might be needed.
Since you want to use them solely for GPU cooling, you might want to get a thermal probe for the fluid temperature if your board supports one, that might be a better indication than CPU load temps.