Car Stereos: replacing monsoon stereo system in grand am gt, monsoon stereo, good speakers

Question
i was looking into replacing my stock deck and was also thinking of installing all new speakers and speaker amp and sub and sub amp. i had been told at an audio visual store that you have to bypass the stock amp and not only that but that i will also have to put all new speaker wiring through the car.  got a quote and it was outrageous of course so me and a couple friends were going to do it ourselves. i'm wanting to know if you do infact have to run all new wire, if so how difficult would that be and i was also wondering where the stock amp is located and its accessability.  i'm also wondering how much and what type of wiring i would need to run for the speakers and subs and amps and what harnesses and other equiptment i would need. i have an idea on it i'm not totally clueless i just want to do it right the first time. also want brand of wiring recommended like JL or monster or what.  i dont know the best quality for a decent price. i understand that the amount of cable will depend on where the amp is located, i'm guessing i would put the speaker amp under the front seat, save on cable distance wire distance and put the sub amp in the trunk with the sub amp. i'm just unsure about all this stuff because i dont feel that i can trust the place where i got the information from, their quote for speaker wire was a dollar a foot and he figured they would need 65 feet which i couldnt see happening but i could be wrong. but anyways if you can help me out or if you can point me in the right direction for help if you dont know that would be great thanks.

Answer
Mat,  Unless your radio does not have the features that you like, or is not working properly, I would suggest keeping it.  Most OEM stereos are high dollar units made by the top Stereo manufacturers around the world.  A cheap replacement will not sound as good.  Speakers, on the other hand, are about the worst money can buy.  They are made to specific OEM specs and that is it, nothing extra.  I would suggest definitely replacing the speakers with any aftermarket speakers (probably Infinity, MB Quart, or Polk Audio).  Aftermarket speakers will totally change the way your car radio sounds.  IF you are adding a sub and sub amp, it can be wired from existing wires in the trunk.  So, your sub and sub amp would require about 20 feet of wire, but not $1 a foot.  Probably about $.30 a foot.  If you do choose to replace the stereo, I would go to crutchfield.com and enter your exact make and model car and they will tell you everything you need for the installation.  If you buy the stereo from them, they will give you all the installation stuff free.  Hope this helps, Scott