Hi. I'm about to install a second hard disk into a 2011 mac mini. I've bought the cable from MacParts Online. I was wondering if it's really necessary to install the rubber grommets and screws, as they are really expensive. (about $40). Does the second hard drive fit very loose? Does anyone know or can measure the size of those grommets?. I'll try to find them in a hardware store. Thanks a lot.