I'll chime in. I have a Pioneer head unit, 22wx4 OR 22x2 and 70wx1 @2ohms for a sub. I've got a good pair of JBL 5.25" speakers in the door and a 6.5" dual voice coil Bazooka tube in the back. That's it. The DVC tube runs at 2ohms which makes the most out of the 70w being fed to it. No external amp. You can get a mid-level Pioneer or similar head unit for <$150, good speakers for <$100 and, IMO, you can probably find a used Bazooka for $100 or less. An 8" dual voice coil tube will give you some more bump if you want, but the 6.5" will really surprise you with how hard you can drive it and it snugs right in behind either seat and does not limit the seat from going all the way back. There's my nickels worth of opinion.