Will it run on a Macbook with an X3100 graphics thing? How well will it run? Will it run on a Macbook Pro with a 8600m GPU? How well? Which would be better to get: Mac version or Windows? I dont midn running windows provided I get noticeably better performance. What advantage is there in buying it through Steam? If I have it in Steam, I know I can play it on different machines but only one at a time. So do my saved games get transferred too? Say I play it on my desktop and save a game. Will I find the same saved game updated onto my laptop when I go on to it to play?