I'm with Genghis. Harry's A40 headsets and intercom work fine in a Cub, even with the door open. I use an Icom A3E connected to a roof arial and I get 30 miles plus. Batteries are expensive (£60) but it's worth having 2. The intercom uses a 9v square torch battery which last for ever. A good point is that the headsets have the PTT button mounted on one of the earpieces which works brilliantly.
The fee for a handheld has been reduced to £20 cos us primatives can't afford real radios.....