I am running this on my 2011 JKUR with a 6 spd. I run the 91 tune and I think it made a little difference but I don't have anything to back that up. I mainly bought it for the other features. I would probably buy it again, just don't expect to win any races. I get about 15-16 mpg around town and maybe 17 on the highway running stock tires and the Gobi rack doesn't help.
We tried running one on our 2007 JKUR with a 3.8L and a manual and honestly, I can't say it made much of a difference. And, just so that it's clear, I really like the Flashpaq and have used them on my old 2007 JK 2-door and 2009 JKU that both had an auto and thought that it made a noticeable difference on them.