Thanks Scotty, It's not as if I will be towing at 100mph. It's just to tow my trailer to the rubbish dump approx 5 kms away. I've had a search but it looks like I may have to try 3rd party towbar and get the wiring loom from audi for an A4
Officially no, but as the same body is used and the mounting pints are the same it will go. The only issue you may have is trimming the rear lower valence as the s4 bumpers are different. Persevere with the bumper and everything else will go no worries. Also use a genuine Audi electrical kit as it CAN controlled and can go wobbly if not coded correctly.