ETKA does not have a part numberfor the RS4 turbos, but I think this is the number.

But, I just found this from a post (via AW Search):

078 145 703M = K04-25 = driver side
078 145 704M = K04-26 = passenger side<ul><li><a href="http://forums.audiworld.com/s4/msgs/1471915.phtml">AW search found this post...</a></li></ul>