Now that i done all the installation of a new pioneer dvd units in my car . connect my old stuff from previous car Cadence Mono Block amp and a 12" Sony Subwoofer . Music sound better than stock HU but i want more .

Done some reading and people recommend to invest only in front speaker and leave rear speaker to OEM stock .

I having a look at those few speaker as my budget is $300 or under all price quote from www.ryda.com.au pioneer stock discount deal from a friend . JBL is good brand but i never had one install in car before , i got Pioneer TS-C1602 2 years ago in my old car and it make me happy

Pioneer TS-D1720C : $260 ( ryda $310 )
Pioneer TS-A1702C : $200
Boston SX60 6" : $277
JBL P6500 6" : $330

The question is what brand of the stock speaker Euro 04 using and if i upgrade to one of those speaker above will i notice much diff in sound quality or you need to buy those high end at $600-900 to hear the diff ? Should i connect straight to headunit or invest another $200-$300 for another AMP to power up new component speaker . I normally listen to rnb , pop music and mostly radio 96.1