Resolving dimming lights

like a lot of people I have a problem with dimming lights (headlights and interior, dash).  I read the other post on dimming lights and it didnt seem to help , I have done all that.  I drive a 1990 VW Golf, it came with a 65A Alternator, and I had the 90A version rewound to pump out 110A; I was told that this is the highest value I can have on my car without custom brackets installed.  I have also installed a 650CCA battery in my car, and installed a 1Farad stiffening cap to try and resolve the problem.  for Amplifiers I am running a Rockford Fosgate 800.2 (1020W RMS) and a RF 200.2 (210W RMS) both amps are fused then fused again at the battery with a 60Amp fuse.  So thinking the car used to run with 65A, and I had a possibly 60A draw that the alternator almost doubling the output would help.  (yes I was running the system on the old alternator). But the lights dim very much.  The voltage reading on the cap at normal operation is 14.98Volts, then when the bass hits it drops down to 12.6V.  I am running 4Guage wire all through power and ground, and the cap is mounted less than 10" from the amp.  The grounding system uses the chasis but has 2 4Guage wires as ground at chassis and battery.  Alternator wires, and everything is 4 guage.  If I run a ground from the amps stright to the battery that shouldnt make a difference right cause I have adjusted to the cable size at the battery.

I am just wondering what I can do  to try to if not eliminate this problem, how can I help it get better?

I know of a few products such as the AccuVolt by Jacobs electronics which is basically a voltage regultor/conditioner which claims to keep a constant voltage all the way up to 16V I believe.  Before buying one I was wondering if anyone has used this product and do you think it would help my senario.  I can get one here in canada for $425 at a disco'd price... its not cheap, but if it works, I'll get it.

Another product of interst is the BATCAP by Xstatic which is a battery that has a discharging rate of a capacitor, and they claim is equivalnt to (100) 1 farad capacitors,  and it goes for like $170USD.  But can that really be 100Farads??? that seems worth it but will it help me?

I've heard that adding another battery such as an Optima Yellow top will only help if you wanna listen with your car off, is that tru or would it help me? (I only listen while driving)

product links:

I have another 800.2 amp that I plan on adding, so thats a 2000W rms output with a possibly 120A draw.  Im not going to do that until I can solve this problem though.

Your opinions/experience on those products are valued, and any help you give thanks in adavance.

Matt (Vancouver B.C. Canada)

Just keep adding a farad untill the problem goes away.

Each car has differant properties.

Each system has different properties.

A second battery will help nomater what

Thanks Patrick I will give you a call sometime soon maybe not till next thursday cause I work graveyards... we'll see.  I appreciate your help though.  Hey I am from surrey too, newton area.

***