I've just got my 13'' mbp replaced due to imbalance or wobbling problem. But the new one also have the same problem. Well, maybe not on certain desk it doesn't wobble. obviously prove some desk are not straight or flat 100% But I have test it on one of my table with along a 15'' Mbp yet the 15'' sit just fine on the desk while 13'' wobble quite much. It maybe a different in the unit's weight? or maybe the length of the 13'' mbp is shorter that makes it sensitive than the 15'' which is longer that will sit fine on most table. But what I'm curious now is, what about the previous unibody macbook? it is the same size, but I've never heard anything much about imbalance problem on it instead I've read alot of people here got this problem with their 13'' mbp.