I'm sure some guy with more money than brains has done it just to say he did it.
Dumb idea on any 4 cylinder car, weighty, no performance gains whatsoever, costy. Some manufacturers still put a dual exhaust on 4 bangers, but only for aesthetics or to change the tone. The Dart is a good example, the 1.4 sounds pretty throaty for a 4 banger, but it's gutless. That's why they do it, create a feel.
Dumb idea on any 4 cylinder car, weighty, no performance gains whatsoever, costy. Some manufacturers still put a dual exhaust on 4 bangers, but only for aesthetics or to change the tone. The Dart is a good example, the 1.4 sounds pretty throaty for a 4 banger, but it's gutless. That's why they do it, create a feel.