What kind of fans. Oscillating or vent fans.
Vent fans.....on my Vortex, I bought a 30 dollar speed controller, and insulated flex ducting. The speed controller makes the biggest difference, while making virtually no difference on function even when dialed nearly all the way back. At least in my room. You can also build a box around the inline fan if needed like suggested in the Odor Control thread.
Oscillating fans........I remove the cage, seems to help a little bit of the noise. Wall mount ones are tricky, especially if mounted on a thin wall. They act like a drum it seems. I always try to mount to the most sturdy wall if possible.