I also second the motion of installing amps under the seat.. that is if you have room. The two cars I've owned have had enough space underneat their seats to install a 40-watt Kenwood amp no problem.. I didn't even have to take out the seats. Of course I am the king of hacked-up installations of stereo equipment. I ran my amp off the cigarette lighter for about a year until my electrical system started to do weird stuff. If you just want to get the rio installed quick and cheap get a 40-watt amp and throw it anywhere you can find it, under seat, in glove box whatever