I had a killer system with JLs in my 2001 that I just sold. NO noise.

1) Always run hot and remote wires down passenger side
Run RCAs down driver side away from catalytic converter heat.

2) Never run cheap RCAs. Spend $100 and get good ones. That's where your sound comes from.

3) Get capacitor caps and run them inline between amp and battery. This will store the power you need when playing high volume and subs are hitting hard. No capacitor = weak sterios, lights blinking, excessive alternator drain which can lead to noise.

4) Ground each amp separately. You can connect the hot wire to one amp, then cut a foot or so, and go on to another amp, ect. But don't do this with the grounds. Run them separately.

Hope this helps.