Id say do the muffler if your going to do anything because honestly you aren’t getting much bang for your buck doing exhaust on a V6, especially a turbo engine. Engine sound harmonics and Exhaust note is more of a science than we think. A V6 engine isn’t going to get a deep throaty sound of a bigger motor and the reason stems back to the pulses coming out the manifolds (smaller bore and 3 pulses per side) and on top of that your running it through a turbo which eliminates any harmonics it would have had beforehand. Generally the bigger the piston bore, the deeper the sound (think 350 vs 454 big block exhaust note). All that being said it’s up to you but your not getting the same bang for your buck IMO, lots of times it just sounds a bit more raspy on a smaller motor. Just stating what I’ve observed in the past.