I want to replace the hard drive of a rev A g5 iMac and I see that currently it has a sata 1.5gb/s hard drive. Could I get away with getting a 3.0gb/s or is it incompatible? Specifically this one: http://www.newegg.com/Product/Product.asp?Item=N82E16822136003 . Thanks for all of your help! PS- I'm trying to find an enclosure that is firewire but will allow me to hook up the sata drive i take out. Do they really exist? I'm having the most difficult time.