This will be our primary family computer (and the last PC to be replaced in the house)....Can I only purchase with 8gb of RAM and then buy aftermarket through crucial.com to get it to 32GB? downsides to that? Setting up this iMac for my wife, myself and two daughters....3 different accounts, no imessage intergration on either one....how about music and iTunes? I have a HD of music downloaded and (in some cases) purchased by me....will that share across both accounts in iTunes. Any other suggestions for the new setup?