Alpine White? 
Did you special order that color through the Audi Exclusive option or something? Or did you really mean to say Ibis White. (Alpine White is not a standard color available on the S5.)
You won't be able to fit the Cayenne exhaust tips into the factory rear valance openings. You'll have to install a Rieger rear bumper add-on plus their rear valance. (See attached photo.) And personally, I don't think that Rieger add-on bumper piece looks good because it looks like it was just slapped on (the side piece too) and does not integrate well at all with the rear bumper cover.
For the spacers, you can get them at MadAudi Design or Pure Motorsport.
Did you special order that color through the Audi Exclusive option or something? Or did you really mean to say Ibis White. (Alpine White is not a standard color available on the S5.)
You won't be able to fit the Cayenne exhaust tips into the factory rear valance openings. You'll have to install a Rieger rear bumper add-on plus their rear valance. (See attached photo.) And personally, I don't think that Rieger add-on bumper piece looks good because it looks like it was just slapped on (the side piece too) and does not integrate well at all with the rear bumper cover.
For the spacers, you can get them at MadAudi Design or Pure Motorsport.