I have a 12v dock for my Sirius...and I've never liked the way it
fits...either with the suction cup or those cheezy clips.  I was going to
build it into the hole where my ashtray currently lives somehow...until I
just happened to try to actually push it down into the ashtray.....It sort
of 'snaps' right into the tray somehow...doesn't rattle or move around, you
can actually  see the display and you can just snap it right out (the
docking station and the radio, as one unit)  and take it away with you,
leaving your ash tray 100% original.   I have an additional power point up
on the dash above mine...I use that for cell phones, etc...and for the
sirius radio now..

  How often does that happen? something just snaps into place without any
modification or fitting or work?

  I put a couple of photos into my Google webpages below, the first link
line.  The second link is to other 'brilliant ideas' I have come up with
over time for my somewhat utilitarian low top home-grown Westie-wannabee..

https://picasaweb.google.com/dhanson928/SirriusMount#

https://picasaweb.google.com/dhanson928/VanagonMods#