The important thing isn't so much the radio as the antenna. The rubber duck
simply won't work as well as hooking the handheld directly into your
comm/nav antenna.

Most avionics shops can install a small jack where you can plug your
handheld that will utilize the plane's antennas. The range and clarity
difference is dramatic. You can then also plug your headset into the
handheld and work directly through the portable.

The comm portion works great, but I haven't tried this with the nav.