Hi - wanted to get your opinions. I'm probably going to buy the base model 13" retina macbook pro. My main concern is the 4GB RAM. Here is my particular situation: I'm selling my 2011 macbook air to my sister so the cost to upgrade will be only a couple of hundred bucks. the air suits my needs perfectly fine, but I want a new computer simply because of that: I have the upgrade itch, I want the retina display, and it's not too much to upgrade. my needs are VERY basic. i literally just go online, listen to itunes, use iphoto, etc. nothing intense whatsoever. 4GB RAM is plenty fine, right? the ONLY reason i am asking is because of the retina display - i don't want there to be any lag, etc. not sure that is even affected by the amount of RAM, but wanted to ask the question. thanks in advance!