I use a Weber lid on my UDS and have to almost close it when using my Pitmaster iQue. I open it up if not using a forced air controller. I have never had issues with temps but I don't go over 350. If I have a need to go over that I use the Weber kettle.
Fired Up Smokers KCBS Team, Smokey W's Pit Que NCPC Team / 2011 NCPC Whole Hog State Champion