It seems if one were to go the rebuild route it would take a full engine rebuilt to upgrade from the standard fsi V8 to the rs4's fsi V8. This could be expensive assuming one could even find the parts. On the other hand one could purchase a rs4 engine and swap it in relatively trouble free it would seem. Will it be possible to purchase an rs4 engine from audi or elsewhere? If so where should i look and how much should i expect to pay? I guess you could even find one is a salvaged rs4/r8 but i dono how to run a google search on scrap yards lol!

Let me get this straight. You want to buy a brand new S5, and drop an RS4 engine in it (thus voiding it's warranty), 'cause you can't wait for the RS5. You must be very rich.

Koz.