In my time on the road I've noticed its the model of Audi coupled with the type of driver:
Audi A1 = over 30, usually a mum with kids of school age/older, carefully and cautiously driven
Audi A3 = can be as above but if its older than 10 or has a driver under 21 it will be driven, generally, by an arsehole
Audi A4 = generally a company saloon. If it has a lone driver in a suit behind the wheel, will be inexplicably glued to the bumper of the car in front regardless of road/weather conditions.
Audi A5 = despite being amazingly beautiful and fast, always seems to be driven well (disclaimer: I do not own one but very much wish I did)
Audi A6 = old man's car. Will be sat in the middle lane of an empty motorway doing 57mph, driven by someone called Fred who belongs to the golf club and wears driving gloves.
Audi Q5/Q7/TT = driven by, with a rare few exceptions, wankers of the highest order with no regard to the personal safety of themselves or anyone around them