OK...first of all look here... http://lexington.craigslist.org/pts/951982317.html

 

Looks like he's got a b5 s4 with navigation. He's confused about whether it's rns-c or rns-d...I can't tell in the pic, but it looks like an rns-d. Well, I guess this will fit right into my 2000 a4 correct? I cant find hardly any info on an rns-c but I do know that the rns-d went in the b6's and the rns-e in the b7 and up. So did the rns-c go in the b5's?