My RV6 is equipped with a 403 stereo intercom. After flying with it for 14 years I have been totally satisfied with it. Very good sound quality, very effective squelch and works great with music. An excellent unit for a reasonable price. I also have Flightcom Denali active noise cancelling head sets. The Flightcom folks are great with product support after the sale too.
Martin Sutter, RV6 2400hrs