Since there seems to be be quite a few problems with core temp and other programs not reading/calculating temperature on all cpu's or at least in sub zero range very well, as it seems from some threads here, this has been suggested by a friend engineer to me when we were chatting. Is this reasonable? Seems to me a pretty good way to go about it.

Make small hole in IHS and use a K type probe with a non conductive TIM to get a direct reading on the core. Granted you should know the internal layout to land the probe on it and not miss