2001 eclipse sub, amp

I just installed a Kicker CVR12 with a 1000W MA Audio 4-channel Amp and i am having two problems.....1.)  I hooked up my sub to channels one and two and i connected my 2 front speakers to channels three and four hoping that it would make the sound from the speakers more loud, crisp, and clear.  They are factory speakers, but they are Infinity's with 210W. I connected the wires using 16 guage wires  and I'm also running the RCA wires to a input converter because i have a factory head unit.  The problem is that everything works except for the front two speakers.........2.) There is a pretty significant "ringing" sound coming from my 2 front speakers that increases as my RPM's increase when i drive.  Im almost sure that it is because i dont have a good enough ground.  My amp is mounted on the back of the back-passengers seat and only have about a 3 foot ground wire.  Does anybody know how to fix my speaker problem or know where i can hook my ground wire up so the ringing goes away???? Any advice  from anybody will be very helpful

The ringing is called "alternator whine."

Making a good quality ground isn't really hard - sand down the body paint and bolt thing thing to the car. . .

How do you have it grounded now?  Why do you think its the ground?

right now i have my ground hooked up to a bolt on the floor of my trunk.  I think the ground point may be a little too far away from the amp.  could there be interference with the other rca and speaker wires and the ground?? and do u kno how to fix my speaker problem???

Did you bypass the factory amp when you wired up your front speakers, or did you just run wire from the amp, directly to them?

If you didnt bypass the factory amp Im going to guess that may be your problem, but someone please correct me if Im wrong. Im not too familiar with car audio Im more of a car security guy but if you send 2 sources of signal to 1 speaker (by signal I mean an output from the factory deck, and the output from the amp)... The sound from the speaker isnt something desirable right?! Or am I wrong?

If you're really concerned about where you grounded it I have my ground in that little "hump" area right behind the rear seats on the bottom. If you didnt notice I do have the same car as you ;D and thats where I have my system grounded. You can try grounding yours there too but as stated above sand down the area to be used as ground to get off paint/rust till you see the metal turning silver.