Is there any way you can run dual exhaust without making it sound louder than stock?

 

ya, ensure the muffler(s) has alot of baffles and you may want to get a smaller tailpipe diameter

 

Baffles aren't the only way to muffle sound. Perforated straight through mufflers are a better option. A larger 18" or 22" muffler on each side behind the cross over would do the job admirably. Pipe diameter doesn't affect volume, only tone. Stay with a 2.5" for duals if smooth bent, if all mandrel you can go to 2.25".