I can’t speak from a more professional standpoint, but I’m in school for media production (so I’m on a budget) and I ran FCS2 (then 3, after it came out) on my 2.4ghz Intel Core 2 Duo 20″ iMac with only 2GB of RAM from 2007-2011. All applications ran fine for me, even working with multiple layers of HD footage in a sequence that ran for several hours. With that quad core and 4GB of RAM, you’ll be fine – in my opinion.
You will have to purchase more hard drive space – a terabyte will fill up faster than you think. I daisy chain several terabytes off of my iMac.
Fun fact: that 20″ iMac is still running strong. I gave it to my dad when I upgraded to a new iMac recently.
– David Sikes