How do you notice the difference between sports exhaust system and series? (optical)

Hi Forumlar, my question is actually already in the subject How do you notice the difference between sports exhaust system and series? (optical) Was today with Audi and the seller also net could tell me directly whether on the one R8 sports exhaust system was installed or not. The flap button on the steering wheel you get with the more expensive steering wheel but how do you notice that besides looking at the equipment list?