i did it the easiest way possible- broke the center plastic+motor/blades out of the noctua housing, trimmed down the excess around the center plastic piece, and then double-sided taped the center plastic to the original mounting point on the heatsink. the hardest part was actually having to use a dutch vpn + paypal + german package forwarding service to get the 14-pin adapter from arctic cooling.
i think there's a full guide on sffpc about reusing the mounting from the original fans and such so that it's more secure/better all-around, but i wanted to be able to restore everything on the gpu back to stock and the double-sided tape has worked in all orientations without any issues so far, so i just left it this way.
cooling-wise it was probably a marginal improvement over the stock fans (i can't really remember tbh, i did this last year and i've barely played any games in 2020), but noise-wise was a noticeable improvement in terms of both volume and profile. i'm pretty noise conscious, but i ramp the fans up to 100% at 50c and i don't remember hearing them at ~3ft with closed headphones and ~40% volume in the few games i played. all other times i just run them at 30% and they typically keep the card under 30c while being effectively silent.
