I want to use my MP3 player with the standard headunit in an 07 WRX, will this cable work, has anyone tried one:

Car Audio Direct - The UK's leading car audio and stereo resource. Kenwood CA-C2AX - Kenwood KEN-CAC2AX (http://www.caraudiodirect.co.uk/kenwood-cac2ax-p-4635.html)