it depends on your price..goto someplace where you can test the equipment. IMO Best Buy is the best place to go (around here atleast)
I dropped 800$ for 4 good speakers, a good amp, and two shitty subs. Sounds pretty dope, I need to get better subs, but I don't think you're going to be like p diddy and have 1651654 subs in your car. So go test it out, I'm sure you don't need top of the line. Its like a computer. A weak computer can still run outlook, you don't need a top of the line pc to surf the web and read email.