if you're going to replace fans, go for Panflo, maestro speaks highly of them, and i just ordered two 80mm's for my upcoming case, they're AMAZING also, if you wanna risk it for a biscuit, glue them in. no screws = almost no vibration
also at xpcgear.com you can get vibration dampening kits its a little rubber thing that goes around the fan if you took a look at it, im sure you could just make your own, save a few bucks