Matt, the 20' Monster cable is $106.00 from Wild West Electronics.
Kyle, I cannot find the link. However to select the AUX input sensitivity on a Clarion XMD3: Prss and hold the "T" button for 1 second or longer to switch to the adjustment selection display. Pres the side to side arrow button button and select "AUX SENS". Press the up and down arrow button and select "HIGH". Press the "T" button to return to the previous mode. You can down load the XMD-3 owners manual from the Clarion web site. I hope this helps good luck.
Oh ya one last thing to complicate things a little. I plan on taking Grants advice and getting a line driver. This will boost the signal of the preamp output. I believe Harold said it made his I-pod sound like it was on steriods. Good Luck.