I have never used one in mine and thought that was the beauty of a UDS...
How do you think it would improve the performance any or are you just trying to introduce flavor with something like apple juice?
i have never used one in my uds but i do use a heat deflector.
I don't use one often , but when I do one of these works well http://www.academy.com/webapp/wcs/stores/servlet/Product_10151_10051_91711_-1?N=77985508+933739030