Bear in mind the majority of aftermarket exhausts don't use the same construction method, materials or pipe diameter as OEM, so the sound levels will always generally be louder.
If you get the quiet spec option, if available, it should be relatively well mannered.
When mine finally lets go (it's annoyingly still hole free after 13 years, amazing!) I'll be importing a Techtonics Tuning or Magnaflow system over from the states. I would get another OEM one but the price is too stupid to even consider it.