We found the airbag needed for this swap in a local junkyard from an A8. Just trying to find a wheel for a fair price. Hopefully the airbag fits, according to the internet the A8 airbag works. It's part number 4E0880201 BH 6PS
The + - dont work on the rs4 steering wheel but does on the R8, reason being the wheel is taken off a gallardo and it was only meant to be a one off, which is why it works if you get basically the same steering wheel off an R8
Be more specific when it comes to torque specs bro. Your torque wrench clicked of without any movement of the nut. That says you have exceeded the specification you dialed into the wrench. Be careful not to overtorque and squash the aluminum on these steering wheels as the metal is soft and mostly hollow. Car sounds good. (Supercharged?)