Viper, sorry for the delay. I just ordered my RA4 from OEMAutopartsco.com. The price is $999.00 and shipping is free. The radio comes with a 30 days warranty and they offer a 1 year warranty for $149.00.
Hopefuly you read Trickster thread on how to mount the radio since the braket does not quite match the one in the car. At any rate you can find the thread here: http://http://www.challengertalk.com/forums/f202/2015-challengers-337258/
Hope this help.