i have an RC3 and absolutely love it.
it would be hard to judge just how noisy one is but to me I think it's rather tolerable.
Unless you ride around with your clutch engaged (left foot on clutch pedal pushed in) then you won't hear any noise.
While at traffic light's I’m usually in neutral unless a poopie head mustang

or a silly 4G63

pulls up next to me. For sure, I get ready with the clutch engaged and begin spooling the turbos prior to my yanking it just as the light changes.
Prior to this I had a SB FE Stage V and it was fine.
But then I got an RC3 (Triple) and ironically it's great all around. City and traffic is not as harsh as some ppl make it out to be.
My car is in MD so unfortunately I can't make any clips...but will as soon as I head back.
On a biased scale of 1 to 10 (10 being the loudest averaging 106dB) I would submit that it's b/t 4 & 5.
OS Giken clutches were designed around Nissans anyway so you won't go wrong with support for that matter. IIRC, the a new sleeve is the only thing that's different in the RC3 however the twin-disc OS Giken’s should be a snap to install as well as other twin disc clutches.
Let us know should you decide.