Thanks for your reply! very helpful.
Noise will be reduced but what about the radiator fans? I guess they might be loud too?
There will be some noise ofc. But its nothing compared to air-cooled systems. Some kits are designed to operate as silent as possible.
They also come with a fan speed controller which can be used to control the speed and so on. However, you should be careful if you don't know what you are doing - dont lose sight of the temperatures of the hasboards.