Originally Posted by NickTurnon

the question is do I need to buy a new head unit? If you just wanted to run an amp and sub, then you wouldnt need a headunit. But you also would probably not like the sound because the stock speakers would be over powered. Most of the time people that buy a system replace the stock speakers in order to compensate for the added bass.

I think I saw one thread said If we want to put sub and amp into Z, we need to buy a new head unit because the stock+ converter may not work properly, and head unit itself is about $500+. You can find a good double din with ipod, bluetooth, etc. for $300-500 thats NAV Ready. If you want just a double din, you can pick up used ones on the forum or buy a jensen or something for $200 bucks. At that price I would add some more cash into it and get a wing instead, If you dont have a wing, search on the forum for WINGTECH or look on my build page. I paid $130 bucks for the sport spoiler and thats painted brilliant silver and shippped. and how much would be the cheapest that I need because I know that one of my friend he just bought sub and amp on his own and then he paid to someone to install it for him, so he ended up like just 300-400 bucks If your friend bought a subwoofer and amp for 300 bucks then my guess was its low quality. You can go to walmart and buy a complete system for about $200. Install would cost you $50 if you found someone on craigslist.

My suggestion, buy a decent headunit on ebay or amazon. A good unit will give you an additional 50 Watts to all your speakers. Itll help make the stock speakers sound better. As far as bass goes, a few people installed a little built in enclosure built by infinity. Its a small 8 that just plugs and plays. Online they are about $180 bucks. That might be a good start for you if you are on a budget.