I added a Puron to the wall outlet that feeds my Puritan 156. The improvement was instantaneous. Everything is more textured with a slightly bigger soundstage. The bass also seems a little deeper. After 48 hours of being in the system the sound really didn't change. However, when I unplugged the Puron the sound did go back to what is was before. So, let it "burn in for awhile" really didn't apply to my system for whatever reason.
Based on everyone's comments, especially Ozzy's, I ordered another Puron from Mark and will be using it on a plug extender into the same wall outlet the current Puron is on. Great product and looking forward to the results when using two of them.