Well after some experimentation:
I went ahead an unmounted everything again, to validate there wasn't a problem with the seating... only to find that it was pretty much perfect to begin with. The chip surface itself is somewhat uneven, but honestly I don't want to go through the effort of lapping...
Having explored various fan controlling options, I have come to the conclusion that 40-50C idle temperatures are probably not all the uncommon for a silent build, and that apparently Intel (at least in their motherboard BIOS) appears to believe that 70-75C is range when the chip starts to need additional cooling.
Auto RPM control @ idle (50-150rpm): 45,43,43,42
Manual RPM control @ idle (800-1200rpm): 34, 32, 32, 31
Auto RPM control @ peak (600-700rpm): 73, 72, 72, 69
Manual RPM control @ peak (800-1200rpm): 63, 62, 62, 59
Having spent hours reading/searching/asking, the general consensus seems to be that people are horribly confused. While a great deal seemed to indicate their processors idled in the mid 30's, and peaked in the upper 50's, they rarely made mention of their fan speeds, and the ones that did all ran in ranges way outside of my acceptable audible range (1900-3000rpm). This all of course is also neglecting that their main system fans are running way higher then the 800rpm range as well.
So i've come to believe that the Mugen 2 is doing a fairly good job, and really it is a matter of airflow... I may swap the stock fan PWM fan for a constant RPM fan that perhaps runs a little slower... or I may just let the system idle a little higher then the "norm".
Thanks everyone for the input