What he said X10That's a bigger question than it would seem at face value. Does the vehicle you want to install an XM radio in already have a radio? If it does, does the existing radio conform to the DIN standards, or will you need to adapt? Do you plan to have your new XM radio mounted in the dash or somewhere else? Do you need your new radio to have any weatherproofing because you don't run a top? Do you plan to run existing speakers; do you plan to upgrade the existing speakers to better take advantage of the digital signals; are the existing speakers rated to handle the power of the head unit you plan to use; do you plan to add additional speakers, subwoofers, etc.? If you have an existing radio, is power wiring sufficient to power your new XM radio? If you have existing speakers, is the wiring running to those speakers in good condition; is the wiring sufficient to handle the power from your new head unit? Are you planning to add additional amplifiers?
There's a lot of base questions that need to be answered before a list can be created. There's also so much variation in end-user setups that a list would likely be useless.