Hate to bring up the dead. I just purchased a 4pk. Should I have gone with the 4pks? I have the 3pks now and have no issues with it. But it is time to upgrade and my girl gets to reap the benefits of a free 3pks for her 4x4 sc. Not into crawling and use LIFE for batts. Is the speed differance really that much? Will I even be able to notice it? Thanks!