Quote Originally Posted by mortis View Post
First advise sq gurus give is not to upgrade the rear speakers, and nost would even disconnect it. The principle is that when listening you normally like the sound stage to be up front and center. Normally you would like rear sounds only for movies...

The subs would be able to produce lower frequency sounds that your rear speakers either wont play or would play poorly. Downside with subs is that they eat up space. Suggest you consider this. For me I opted to use a customized fiberglass enclosure created by Jonz of simplesounds. More expensive than the regular mdf box, but it allowed me to have trunk space. Di halata ni mrs na may subs kaya happy wife, happy life.. He he
+1

In car audio, there is more emphasis on sound coming from the front. In tuning, most would have their car audio system front-biased. The rear speakers will not help in such a case. If using more capable head units with time alignment, you can tune it better to your preference.

Using only a good set of separates and subwoofer, you can filter the high, mid, and low frequencies to be played by the tweeters, midbass, and subwoofer. They would be enough to have that decent listening experience inside your car.