JL Audio. Pioneer.
After market head unit, 2 12's, 1000w amp, 2 12" box + wiring. Roughly 3-500$ used. Brand new, well, that's up to you. The only thing I recommend is don't just sink all your money into the sub woofers alone. Get the highs and put some bad ass tweeters in the front. Stay away from USED AMPS though. Tweeters don't get too expensive, but make sure you're amp you choose has enough channels for them and the sub woofers, additional speakers, etc.
But take Chicken's advice. As a growing adult, you should hopefully understand that there is a huge difference in entertainment and function. At such a young age and with a loaded gun (cars are just the same if not worse in lethality) it'd be safe to keep the gun stock to learn such things before you go and put a hairline trigger on it making it fun yet more dangerous.