well, overclocking laptop components isnt such a good idea and after reading this review http://www.notebookcheck.net/Review-Alienware-M14x-Notebook.54257.0.html
with full load temps of 95
c on the cpu and 81
c on the gpu and already a loud fan straggling, i wouldnt try any! insufficient cooling may harm the hardware. also keep in mind that even o/c the gpu only will also affect the cpu temps cause having only one fan means that there is a unified cpu-gpu heatsink!