you dont have to replace them but if you want better sound you should,especialy considering you hear more from them than your rears and if your adding an aftermarket radio you should definitly bypass the bose amps and its not hard at all just run new speakerwire to all 4 speakers and hookit up the the aftermarket radios wiring harness or go all out and bu a 2 or 4 channel amp for the speaker and run the wire from the speakers directly to the amp that way you can have the speakers on highpass for the best clarity
you don't need to run new wires, just cut the two small wires that are going into the bose speaker. you will need to extend the wires a little bit by adding some but that's not that hard at all, way easier than running new wires.
REALLY - you have 4x6 in the front right? get infinity kappas for those...YOU CAN INSTALL them yourself. EASY!! there's nothing but screws holding the door panel in. get an audiobahn sub w/ rockford amp. Good prices for great products.
when i was having my 4 channel pioneer amp looked at, i bought a sony xplod 9?? 4 channel amp until i got it back and tha sound was beautiful....on top of that, my subs 760 watts were connected too and all this on an auotzone battery...lights didn't dim or anything....from what i've heard, just use a lil bigger gauge wire and you should be ok, but with 220, you're more than fine...no new/added battery needed!!