I think it is possible to do a R8/lambo Head swap. install our cams and be able to use a preexisting supercharger kit for the Lambo or R8. Convince me I am wrong and go!
I don’t think so. The cam adjusters and dry sump systems on both of those R8 and lambo would probably cause the timing system to be different. In the case of the RS4 and the Q7 4.2
Also for the money. I would just port your heads chances are they all flow close to the same. Even if you could get the R8 camshafts to go in the power curve of the R8 is to 8k and your transmission controls where the cars shifts and that’s at 6700rpm. It might vary a few rpm depending on how the car is accelerating. but its a big difference.
The camshafts in the S6 are built for low end TQ you would loose all of that if you went to a R8 or lambo cam.
Also for all that money I would just contact JHM and ask to have them get you the supercharger kit they have for the 5.2.
Here is a graph showing how much TQ the RS4 looses lower in the rpm range over the Q7. Now keep in mind that this change is in large due to the difference in the cam shaft profile and how the RS4 camshafts are like the R8 or the higher reving motors.
http://ep1.pinkbike.org/p4pb11204213/p4pb11204213.jpg
The dotted line is the Q7. Notice how the Q7 has more Peak Tq and more Tq in the lower 2000 - 6000 range.
Keep in mind the S6 has a little better Tq range and the cam profile should carry out to about the 6500 to 6800 range.
So again. I think your moving in the wrong direction going with a high reving cam profile. Especially when you consider the weight differences in our cars and the massive need for that lower end cam profile.
yikes went the wrong way on that. I specifically said “install our cams” I want to keep our cams. Sorry if that was unclear. My pont was The heads will match up with the R8 supercharging system. The Cams in the R8 are designed for a shared pin crank. He have the split pin crank similar to the 5.0 Lambo engine Cams wouldn’t even be close to the right cut. looking to keep that power curve lower high end power you lose torq the car is heavy just doesn’t make sense to put a Lambo engine in our car as it is. No i am thinking of a way to cross the bridge with all the research and work that is done for the Lambo and R8 systems and i think our cams will fit just fine into the R8 heads. I think i remember even doing the research and finding all the parts numbers for the intake and exhaust valves were the same.
A few things I would give you to think about.
1 why lambo or R8 heads…
Think about it…What can you definitively say makes the R8 heads better… The valves are the same size. Is this just a thought that R8 hears are better because they are on an R8. When you follow the curve and keeping with the Q7 and RS4 theme for our example. The RS4 makes a lot more hp but that HP is in the cams the head ports and chamber size is the same. So are the valves. The springs might be different and some of the supporting parts but thats it. I don’t see the R8 being any different.
2 If you want more power. I would suggest getting a set of stock S6 heads and getting them race ported.
That is where your going to find the big jump in hp. Open the heads up and let them flow. your likely to find more hp there than in the OEM R8 heads
3 get your cams reground. I don’t know how much money your talking but R8 heads are not going to be cheap. Getting re ground heads can get you more hp. The biggest hang up is how much valve lift room do you have left before you get interference.
To be honest. I think the hybrid route is a dead end. R8 and lambo parts are not going to be the answer. If you want a blower JHM has a great option. I just got one for my S4 and would honestly get one for the S6 when I can finally find a S6 that is is acceptable condition.
As for the S6 take the heads get them ported. Look into headers and the JHM 2.75" exhaust is a big gain there. look into the LW crank pulley from JHM as well. It make a difference. There are a lot of things I think you can do that will have a much bigger payday power wise than going to hybrid route.
As the years go on, the price goes down. 
Not sure what your price range is… buuuuut there looks to be some low mile ‘09s and ‘10s. Can’t speak for their maintenance yet, but it would be fun to look again into the latest on the market.