In the Sept. issue of MAPA Log Trey Hughes asserted that Mooneys were "built by engineers for engineers".   As one of those, I proudly wear my nautical mile wide nerd streak on my sleeve.   When re-designing the panel in our M20C earlier this year, a spare 2-1/2" diameter hole was created for a small accessory.  I found that the good old Davtron 811B served great as a clock/timer and bagel toaster/watt waster, but not much else.  Then I read about the AV-20-S from Aerovonics, which includes engi