What are you using to control the fan speed and are you 100% certain that it's actually running at that speed when you are hearing the noise because a lot of users are not aware that ALL GPU tweak utilities MUST be kept running, as in, do NOT click the X in the corner, instead you must ONLY reduce it to the system tray, in order for the fan profile settings you have configured to remain in effect. Otherwise, the second you close your tweak utility it is reverting back to the default onboard hardware profile and is no longer running at whatever you configured the fan curve to be.
Aside from that FYI, just in case you weren't aware of that fact, when it comes to replacing the fans themselves it's very unlikely you are going to find any other fans that will fit your specific cooler other than the same model they came with without replacing the entire cooler or moving to a liquid cooled option.
Even more so since that model does not seem to be available much of anywhere right now, regardless of region from what I can see. It's pretty doubtful that you are going to find better fans that can directly replace the stock fans on that Colorful Vulcan card. I'm not saying it's completely impossible, but it's definitely not going to be as simple as you think it is.
As far as removing the cooler: