Just received my AC/DC Premium machine and WOW. Yes, I can listen to AC/DC all day, but I also enjoy South Park but wouldn't keep the machine in my collection. So the question I have for you all out there... has anyone installed a Shaker Motor in their Premium machine? If so, is the game play significantly better... do you even notice the shaker is there... or should I just save the money??? Thanks to all of you for your opinions.