So, here's what I've done to the far (2009 D3 S8)....

Carbon cleaned while I was in NY in Feb. (done by a shop in Syracuse).
New plugs and coils done back in March.
New rotors, pads all the way around with fresh brake fluid. (couple of months ago)
Replaced all front control arms, sway bar links and inside/outside ball joints (couple of months ago).

Last week I installed an IMS.
I deleted the flaps because three of them were broken (new IM going in end of year).
Installed an Oil Separator Heater Bypass.
Deleted completely the SAI.
Installed alternator belt.
Installed a lightweight crank pulley.
Drained the power steering fluid. I had the front end completely off (service mode) it was too easy not to get most of that old fluid out. I used a turkey baster.
Drained coolant.
Replaced the engine mount in the front or isolator which was completely sheared which I would not have seen if the front end would not have been off the car.
Fixed bottom lip of bumper that was cracked due to bottoming out on some driveways.
Cleaned sunroof drains and A/C drains.
Replaced battery that died while car was up on jacks while I did the surgery which took me almost a week.

Next…I will buy a new IM and do a JHM ECU TCU tune by end of year. I’ll do wheels after that.

Thank you guys very much for all your input, assistance and knowledge.

Maintenance is the key to a happy well running well balanced Audi espically the 5.2

The JHM tune will transform the car completely. Turning it back into what you would expect to see from a v10 powered car. The nice part is that the S8 has the better air boxes and better exhaust stock than the sister car the S6. While the audi reports show the S6 makes less power on paper that just isn’t very much the case. The exhaust does make a difference and the S8 I believe has a better gear raito but the S8 also has a bit of a sleepy transmission vs the S6 that really responds well to the JHM tune. Hopefully the JHM TCU tune will help change all that but either way. You have done the right list of things and should be very heppy once you install the JHM tune.