[header] How to install an aftermarket headunit in a ford explorer [title] Research head units and pick the one you like the best. [step] Important features are watts, pre-amp outputs (if you want to hook up new amps later), direct ipod connection, and there are many more. [title] Buy the unit. 
[title] Determine if your explorer has the jbl audio system or if it not upgraded. [step] If you have jbl, you will have more work to do, but the end product will sound better.