So I've been reading about drivers but I don't know what drivers are? I'm guessing they're speakers? And another question is it better to buy the speakers separate? Like buying mids by itself and tweets by Itself? I have alpine 6.5 type s components in the front but should I buy mid range speakers and then buy new tweeters? I was looking on amazon and they sell them 1 by 1 not as a pair is this normal? I bought the Alpine for about 120$ is there somewhere better to buy these new speakers that are trustworthy and have fair price for the performance?