My Fusion deck is fully sand and waterproof for the IPOD but the Sirius unit needs to mounted away from the elements like the glove box. I have had the radiator blow on the Rhino and all of the HOT anti freeze blew all over the head unit and no issues... The back of the radio is completely seal. The Fusion unit houses the IPOD behind the Face Plate and has a seal around the IPOD DOCK, most of the head units do not dock the IPOD but have an ambicle cord to the IPOD..
We used to use a marine unit with the marine cover and they would only last about season or so, the CD's and CD player would get scratched or the CD mechinisum woul stop working as the sand would kill the laser.
Either way I just want you guys to fully look at what is out on the market as their are many options and not to many that all weather and element proff.