I received this from the MDRA a couple of years ago when building my RV8.
"EFIS compass is equivalent to a wet compass. However it must be supplied by an alternate power supply in case of an electric power failure. Most EFIS suppliers come with it or can be ordered with standby power. "
I finished my 8 without a whiskey compass and still meet the CAR's requirements.
RV8 Showplanes (although not a showplane
IO-375-M1S with Whirlwind 74RV