Need help with upgrading my existing car stereo system?

Question

Currently i have installed:

sony dash stereo

2 pioneer 4x6's 150w peak 35w rms @ 4 ohms

2 kenwood 6x9 450 watts peak power, 180 watts maximum input power (90 watts RMS) @ 4 ohms

the kenwood speakers are severely underpowered as the stereos built in amp only pushed 20ish rms.. would it be possible to add a 4 channel amplifier to push the back speakers harder and off the same amp power a 12" subwoofer? I'm not exactly savy how amps subs and speakers work so any tips would be appreciated. also, if this kind of setup would be possible what sub/amp combo would be a good choice for a good price? Keep in mind that i'm just 18 yrs old and i'm just trying to improve the setup i have now.

i was browsing newegg.com and saw a few pioneer subs (champion 12") that looked interesting..

Answer 1

It is possible to  run all off of the 4 channel amp, but ur not going to get the most out of ur sub, and u won't be able to tune ur speakers and ur sub separately.  My opinion would be to get 1 kenwood 500 watt to run 4 speakers and a separate amp to run the sub.  You will experience much better sound and maybe save yourself from blowing ur door speakers in the future.

Answer 2

It sounds like you need to take a step band and come up with a plan for your stereo system.  What are you end goals?  What sort of sound are you looking for?  How loud do you want it to be? What kind of music do you primarily listen to?  Is this just for you or are you going to compete or go to car shows?  How much are you willing to spend overall?  Do you want any amount of sound quality or do you want a boomy bass system?  Etc. Etc. Etc.

Once you can start answering these questions, we can look at what you've already got and see what you need to do to get it where you want it to be.  You can't beat a good plan.  

Message me if you want help with this.   Otherwise, yes, you can buy a 4 channel to run your 6x9s and bridge the other two channels to a sub or subs.