Can't Find a aux cord plug in.

So GTA Cartkits plug in won't work in my car as it only has a firmware of 9.50. (GTA requires 9.55). So will something like this work?

Aux 3 5mm Cable Connect iPod iPhone 4 4S 5 MP3 to Mazda Car Player US Shipping | eBay



Edit: So jk that won't work cause its only for 2007+ version of the Rx8. I have the 2004 version.. Does anyone know where i can buy a cheap set up for a 2004 rx8 with 9.50 software version?