I ended up purchasing an ETR-B tensioner for my 08 GF Cobia frame. I have an XT crankset on there and found that when it was installed, the four (empty) posts, where you mount the granny ring, slightly rubbed against the chassis of the ETR-B. I ended up taking a spare 1mm spacer ring from my second wheelset, dremel'd off the three prongs on the inside of it and used it as a spacer for in between my BB and the ETR-B which pushed it out just enough. Is that an ok practice? The spacer fit perfectly...

Other than that, the ETR-B is working without a hitch. It does have a noticeable growl to it though. The only other tensioner I've ever used is a Singleator which I had absolutely no problems with. The ETR-B keeps "teh sex" though... it sure looks good!