After some trial and error, I got my Metro ExpressLanes pass (which is a FasTrak transponder) to work when it is held flush against the plastic at the top-center of the MS windshield, above the rear-view mirror. What are your suggestions for how to mount the transponder non-destructively, that is, without using the velcro strips? If I use the velcro strips, the strips will look ugly when the transponder is taken off, and will likely leave a residue on the plastic. I bought a suction device (JL Safety EZ Pass-Port EZP300) that clips the transponder to the windshield. The device works great on the windshield, but will not stay on the plastic above the rear-view mirror because the plastic is not smooth--it has textured ridges. As a result, I guess some adhesive will have to do, but I would prefer a removable and residue-free solution.