It should work under the top of the dash. I am looking for a way to install something in my 06 Xfire Limited Roadster to add Sirius or XM. I am presently looking at the Kenwood KOS-A200 system that will allow plug-ins for Sat Radio.
On my F350 with the Pioneer Avic D-3 I had Sound Advice install it and my GPS, Sirius, XM & NavTraffic are all under the top of my dah out of site. The only problem I experience is when one of our Florida Thunderstorms is around I have poor reception on everything. I can live with it because I want it concealed.