I had mine on top of the dash, but found out on the road that it bothered my radar detector mounted right next to it.
I considered putting it on top of the clutch reservoir, which seemed to solve the detector problem, but I ended up running the wire back under the seat and right onto the trunk lid. Used a little silicone to glue it on. It's actually on the slanted part of the lid so it faces a little backwards and not straight up. But it works everywhere, just like the same antennae on top of my truck.