The only 6 cylinder vehicle that sounds awesome with a sportier exhaust than stock, IMO, is a boxer 6 Porsche 911. On a racetrack, with a race exhaust, they sound even more awesome, but that isn't for the street.
The current crop of muscle cars sound good with a reasonably throatier exhaust than stock, but unfortunately too many have exhausts that are just ear piercing. Rode in a Boss 302 Mustang that had a fabulous sounding exhaust, Magnaflow 3" with true Y crossover on a highway trip and what sounded good for short trips, quickly became very annoying.
Around here way too many pickups have ridiculously loud exhausts, typically a lifted 1/2 ton, whose owners tear [censored] all over. No idea how they get thru inspection.