I don't see the point in upgrading without upgrading headunit, it will put out more RMS watts to power the speakers. (Tell me If I am wrong but dont yelll at me too much)
My new speakers are
Alpine Electronics of America, Inc. - SPR-17S
and
Alpine Electronics of America, Inc. - SPR-17C
The prices are high on that site but search google, I got them for $220 (all 4 speakers, components for front coaxial for rear), The amp I want is another 240, but you can always just get a headunit and the adapters. I already own a sub and mono amp, where you planing on adding a sub in your trunk?