AC67NOWD

Is it possible to use a eGPU with a Dell Notebook like the E6410, E6510, M4500 with already bulit in Nvidia GPU? This notebook don't support Optimus, and i don't know if its possible to use the Intel HD GMA CPU. (To disable the bulit in nVidia Card and use the intel GMA instead). I wan't to buy a used M4500 or E6410 Notebook, but i'm not sure if it will work with the performance tweak for Optimus. And even if it work with the internal Intel GPU. If someone uses that combination it would be nice to get some more information. Awaiting some facts... thanks a lot.