I am of course talking about the speakers in the door and i do have the premium 8 speaker system which has in the door a tweeter, 4", and 8" speaker.

Currently i have kicker RMB8's straight wired to the wires that where from the old 8" speakers(no amp and they sound fine) I am still running the stock tweeter and the stock 4" speaker and was looking at getting a component system to replace the 4" and tweeters. OH and im still using the stock head unit.

I was wondering whether i should use the crossovers that come with a component set of speakers, if i have stock tweeters? Or should i just wire up the new tweeters to the wires from the old tweeters and the new speakers to the wires from the old speakers?

i figured that there must be some kind of crossover already since i already have tweeters right?

no, you should use the crossover.

as batman said use the cross over its been asked before and its the only way to work correctly

the crossover is attached to the backside of the stock tweeter... you should use the crossover supplied with the new speakers as most likely it is of higher quality anyways than just a capacitor

again you should use the new crossover and you should also look into getting a new head unit and an amp as those speaker will work a lot more efficantly and sound better that way as the unit now does not put out enough power