Before I begin, I must let you know that I am not an expert about this subject, but I do know enough about car audio to tell you about it. The setup in my car consists of the stock speakers. I have 2 12 inch Kicker subs with a Kicker 300 watt amp. I also have a JVC radio installed. There is a bass tuner to adjust bass levels from the radio. I spent about 1100 dollars, including installation on my setup. I am very happy with the results. My next step is to upgrade the speakers, and get a bigger amp. I will probably get a 1000 watt amp. If you are even considering getting subs, do it. I highly recommend it. They are so awesome. You don’t even need to get new speakers for your car/truck. Putting a new amp in makes the stock speakers sound so much better and louder. If you have enough money, it would be a good idea to go ahead and upgrade them, but they are not necessary. Choosing subs depends on price range and size. If you have a small trunk, I don’t think you should try to put in 3 15’s. Make sure the sizes you want will fit. As far as price range, I wouldn’t be cheap when buying subs. Cheap subs will blow easy and not sound as good. I bought some subs on the upper end of the spectrum, and I have no regrets. The same goes with an amp. I would buy a good brand, like Kicker, JL Audio, etc. The more amps, the more sound. Radios are easy to choose. Just look at what would look good in your vehicle. They usually aren’t very expensive. I wouldn’t buy anything used, just because you don’t want things that have been abused by others. In general, I buy mostly everything new, and that is just how I do things. I wouldn’t risk buying anything expensive, like car audio gear, used. My only advice is to listen to everything and make sure it works when you buy it. I would also make sure it comes with all the required parts. If you aren’t a professional car audio technician, I would get everything installed professionally. Installation isn’t extremely expensive, but it isn’t free either. Call around and see who offers the best deal. It is totally worth it. You could install everything yourself, but I wouldn’t want to risk messing up such a huge investment. If you are spending so much money on the equipment, you may as well spend the few extra dollars for installation. In the end, if you buy wisely and choose the right stuff, you will not be disappointed, I promise. If you love music, you need to think about upgrading your audio system. This doesn’t mean you have to buy subs, but it wouldn’t be a bad thing. It all depends on what music you listen to. Upgrading the audio system in my car has proven to be one of the best investments I have made.