Anyone try stuffing their ports?

I would have first tried pulling them further out into the room to see how that affected, but they are already pulled as far out as they can be so this is not an option.

I think ports are used strictly to achieve lower freqs. instead of increasing the size of the box. That said, assuming correct, does stuffing the ports change any other characteristics of the sound other than just low freq. output? For example, if the drivers being ported are also intended for mid freqs., would mid freq sound be affected as well in any way?

Rhljazz - Overall I am very satisfied with the improvements the NOS tubes have provided - they are NOT coming out. However, they do seem to provide deeper and bigger bass so am wondering if this is causing any issues with my drivers (only 6.5" poly) as I think mid bass is sounding slightly distorted now - not exactly positive as have not had enough time lately to properly evaluate. Since I have a pair of powered subs, which never break a sweat as they are rolled in very low freq., am curious what it might sound like if they were given a more prominent role in the mix. Which I intend on trying just for fun and thought one way to do this would be to stuff the ports and raise the x-over. But I certainly do not want to mess up the mid freqs. the mains supply, or the speaker's ability to image well. Thought I'd get some input prior to trying (I am not a tinkerer so prefer to have only a few options to try rather than running the gamut myself.)