To many wires and grounds
 

Ok to keep this short and hopefully simple here are my questions. first of all i did the big three. I also ran a wire from the alt to the battery My grounds were really bad so i ran a wire from the battery to the rear for the amps.
QUESTIONS
1 do i ground all three amps and my wire from the battery to one place (i made a grounding block to do this).
2 plus do i need to also ground my grounding block to the Alero's body in the rear?
3 The wire now coming from the rear of the car grounded with alll the amps and grounded to the body is that wired to the battery or the body or wont it matter with doing the big three.
Thanks Mack

The #1 rule of grounding is that you want to keep your grounds short. A long ground can be ineffective.

The best thing to do in your case was to use bare metal in the trunk area to ground the grounding block so you could then connect the 3 grounds to the block. The battery wasn't needed to ground the subs. Many people ground on one of the strut towers (taking off a bolt from the strut and placing the ground terminal there) or they ground to a bolt that's behind the seat when it comes down. Those are the best places to ground in an N body.

The point of the big 3 is to have a better ground. The only long wire in your big 3 should be alternator (positive) to battery. I also hope you didn't ground your alternator to your battery. You ground your alternator to the car's body and you ground your battery to the car's body. Many people use the stock ground point and attach the new ground.

I hope this helps you out.