Any muffler with a wider exhaust port that allows for a louder sound. Typically found on cars owned by drivers who can't afford a real street-racing car but want to act like they have one.
An exhaust found on a typically shitty car owned by chavs, such as a Corsa B or a 2004 A3. They make a horrendous sound and make the driver look like a complete idiot.
Jon: Listen to the sound of this bad boy, just stuck it on my new Corsa B
Dom: That's fucking class that g, everybody is gonna be well jealous init
Dave: That fartcan sounds shite
Oversize "performance" exhaust found on underpowered import "rice" cars. Generally reduces performance and makes the car sound like it's farting, or like a lawnmower.
A large bore, straight through muffler generally found on four cylinder cars. Usually meant as an insult towards modified import cars, usually said by mullet-wagon (Mustang, Camaro, etc.) owners.