My 07 COOPER S has an mp3 jack STOCK!
 

Back in the spring of 07 when I ordered/purchased my 07 Cooper S, I ordered and received the UPGRADE factory sound system. It is IMO a terrific sounding system. However, I was told by East Bay Mini that I had to spend (think it was around) $350! to have an aux jack so I could run an mp3 player through the stereo. I passed! Now, EIGHT YEARS LATER, I do a little research, then go look at the little cubby hole below the row of toggle switches down below the radio unit, and find a sweet little plate installed UNDER that lip at a light backward tilted angle, with the letters AUX in white on the plate! I haven't an mp3 player to hook up to that jack, but will soon try one out.
I guess I'm a little boggled to think that Mini dealer wanted to charge me a serious chunk of change for something already on the car. Maybe they didn't even know this at the dealer? Things were sort of in flux, (the system in my car, the factory upgrade system, changed to something else as of 08, I believe) so maybe it's just one hand not knowing what the other was doing. Still seem sort of lame.
Let me just say that the 07 Cooper S continues to be one terrific little car.

Great you found it. When the R56 first came out some people did not know much about it from there dealership training and they were maybe thinking of a Gen 1 MINI. In 07 the aux jack was also stock in the R52, which was in the glove box.

Great story and glad you still have it.

hate to break this to ya

but I just checked the window sticker for my 07-S

the AUX input is listed under standard equipment .....

and I seem to recall was described in the owner's manual . . .

when you decide to try this for the first time ... note that there is a way to set the "base level" in the head unit. As I recall they come delivered with set way low, making some folks think it was broken or not hooked up....

you have to select AUX and then go to the settings under that menu item. also if you get distortion, sometimes you need to play with the input level here versus the output level of your MP-3 . . .

You probably already know this, but you don't need an mp3 player, just hook up your cell phone up to it. Also, since you're just hooking up an audio cable, music will play with any audio file your cell phone can decode, not just mp3..

Hate to tell ya this but this forum like many others kinda sucks...A LOT OF PEOPLE HAVE A LITTLE BIT OF INFO...but its not complete...."A little bit of knowledge is danderous"...especially when shared with others...IF YA DON"T KNOW>>>Don't say.