I keep reading about u guys sayin that rear 6x9;s are worthless and not to waste money on em. does this go for all cars ? i got a 99 towncar and was going to upgrade mine, the car has a big interior so i was thinkin it was a good idea, i already go vegas in the front and am going to add tweeters this weekend. the rear speakers have what seems to be like a oval box, i seen it in my trunk (u cant see the speaker, the oval box covers it) i think this probably gives it more bass )not that needed once the systems hooked) anyways what is the deal witg 6x9,s?