kreepa, I would suggest actually reading the guide, very informative. If you are just looking to get to 3 GHz and dont really care, then go ahead and auto clock it. However, you can reach a far more stable and far more maxmized clock if you follow the guide. To me, just understanding why the thing works like that would be most beneficial as you (I) could do it again in the future. The key is stability not speed, Like fetal said, cooling would be preferable. However, it is not always needed, it just depends on the performance you would like to achieve.
Good luck and seriously read the guide, you might find it interesting.