Going with headers and side exhaust will reduce the amount of unsprung weight, so better for performance
If right design would allow changing the type of internal muffler/sound without jacking the car up
Or if wanting to piss off people is taking the mufflers off
Only negative is depending on which type you choose is possible burning legs getting in/out
If going with a full dual front/rear exhaust for better performance is installing an X-pipe close to engine which creates better exhaust pulses that help pull out/ vacate the exhaust of cylinders, thereby the next firing of cylinders is all air/gas and creates better charge to cylinders producing better engine performance