Hi all, I am thinking to upgrade to the new 15" 2.3GHz rMBP with 16GB ram. I am a gamer and currently playing Diablo 3, I've read this game plays amazing on the new rMBP, but I am still concerned: 1) how good other games will do on this laptop? 2) do I need the 2.6GHz model? I do graphic design and some web design. 3) will I be able to upgrade from 256GB flash storage to 512GB on the 2.3GHz rMBP? 4) been searching for websites that does not charge tax, but no luck... Is there any out there? TIA guys!