Could you link me to the Aux Input device? Will it for sure work with our stereo?

If I can't get an Aux Input device I mine as well put in a double din unit. These are the two that I'm looking at.

Pioneer AVH-P4200DVD DVD receiver at Crutchfield Signature

Pioneer AVH-P3200DVD DVD receiver at Crutchfield.com

Either or I'm sure will do the job.

Any other help or advice would be great. Has anyone else even attempted this with the newer models with the monsoon system?