Just answering my own question for anyone who is interested, please correct me if this sounds absurd.

I took the additional heat sink off my NB (EX58-Extreme). I noticed that under load, my NB temps maxed at 54C which is an improvement over the >60C temps I was getting with the additional heat sink on it (will have to do more testing when ambient temp is a bit higher). My assumption is that my graphics cards were heating up the heat sink and therefore making the NB hotter. I first though this might be the case based on the observation that my NB was nearly always sitting on the same temp as my top GTX 260 (up to a certain temp). This was very noticeable after playing a game and letting the system idle. If the 1st GPU was at 60C, the NB was at 60C and they would both cool down at the same rate. Currently, my NB is cooling down and is sitting on 49 where as the GPU is at 54C. If the additional heat sink was on the NB, I would assume that the NB would also be at 54C.