How hard would it be to replace the old tail lights on my 2009 a4 with the new LED one's on the new 2010 model? They look fantastic!

 

If the A5 is any indication, it's not plug and play. Nobody has found a solution for North American spec A5 to go from regular tail lights to LED ones yet.

 

I asked my dealer tech a few weeks ago. He said it's almost impossible (I don't believe him). Not only is the plug different, but he said you need to change the entire wiring harness to account for lower voltage... I find that hard to believe that Audi developed the LED tail lights on the premium models with a totally different wiring harness.

I'll wait until someone smart comes up with a solution. I'll be the first one all over it.

 

Same here. Those LED tail lights are sweeeeet!

 

He's not exaggerating. It really IS that different. You can do a search on this very same topic on various Audi forums. It's been discussed over & over again.