Has anyone had experience w/ these? I'm looking to reduce the noise all produced by all the fans that i have in my case and was wondering if the washers would be a good way to do so. If anyone has experience w/ the products listed in the subject, how effective are they in reducing noise? Thx

Grommets are cheap and good at stopping vibrations going through the case. A cheap method is to use small elastic bands and wrap them around a few times so that they're tight.
As for sound-proof matting, I've heard of some people sticking old mouse mats to the inside of the case.
The sound proofing tends to stop the higher-pitched sounds but you can still get the lower pitched "droning" sounds (or is it the other way round??).
I think it can also up the temps of the pc (varies from pc to pc though) due to increased insulation but if you've got good case fans (on the side and on top) it shouldn't be a problem.
I have invested in a baybus and run my fans at 7v as opposed to 12v, the pc is ALOT quiter and the temps (mobo and cpu) are only about 1-2°C more. If I'm gaming or got music on, I run them at 12v (it's noisier but it's drowned out by the sound of the music or game).
You could also fork out and go for quiter fans (Papst etc).

agree with everything smeggin19 said

I have a baybus and run all of my fans at a max of 7V and its very silent with pax mats installed,but they only stop high pitched noise, and if you can get normal foam just use that

my CPU temp maxes out at about 47 in normal weather and 52 in extremely hot, that's with my CPU fan at 5V though, at 7 it would be down by about 2, and my board work at 28 - 32

Thx for the info. I've got a fan controller controlling 3 120mm in my system. It helped reduce the noise, but i was wondering if the products listed in the subject would help reduce it some more. My fans make a humming sound so I dont think the washers/grommets would make a difference. Thx again