This is a how to for those who may not be technically inclined or just need confirmation on if it is possible to do. My amp would overheat and go into protection mode after 20 minutes, so i installed a 12v brushless computer fan which i had purchased from Radio Shack for a computer mod i did. Needless to say,i ripped it out of that comp and away i went.

Step 1: Preparation

supplies needed:
allen keys
phillips screw driver
wire cutter/strippers
dremmel or other metal cutting tool in your arsenal
brushless 12v computer fan and the 4 nuts and bolts
fan grill/cover

First things first,I reinstalled my amp upside down as there is no venting from the top.The bottom has slits so that should help a little as well. You should probably as a precaution,remove the power from the battery first. as you see i did not,but i am very cautious. remove the back plate. it should be 5 or 6 phillips head screws.

Step 2: Make Your Template

look inside where you want to mount the fan and make sure that no screws will touch anything when your done.Now make a template of the inner diameter of your fan. I used a dirty paper plate because i was too lazy to get something clean:)

Step 3: Transfer Template

figure out where you want the fan. I chose central to provide even cooling but your amp may differ. look for the heat sinks.
Trace with pencil,or in my case since the plate is black,i used a jewelers screwdriver to scratch around my template

Step 4: Cut,grind,drill Etc

double check everything before making any cuts!!!
Now use your dremmel and cut out the template from the plate.
Also make sure you deburr the edges to avoid loose metal falling into your amp. Drill your holes carefully so they line up right with the fan.

Step 5: Install Fan

It is very important to make sure you mount the fan so it is blowing into the amp. if its sucking out it will not be effective. If your not sure which way that is,continue with the next steps but carefully test it out before you tighten it up or secure the plate.

Step 6: Wiring Her Up

remove your ground wire(black) from the amp. twist the negative wire of the fan(black or sometimes black and red stripes) to the ground that you just removed. now reinsert the two twisted wires back into the amp.

Step 7: Positively Not

Very important that you do not remove your red(positive) wire from the amp.
We want to remove the blue remote wire instead. This will allow the fan to shut off and on with the amp. Twist the red(positive) wire from your fan with the blue remote wire and reinsert it into your amp.

Step 8: Finished

Reinstall the back plate,reconnect your battery,and off you go with a nice cool amp.(If you have a yellow wire on the fan too,you can cut it off and wire nut the end,or just leave it as is and tuck it under the amp out of the way.
I have 2 hours (maybe longer but i only tested this long)at full 600 watts instead of 20 minutes now.
My fan happens to have red leds so i took a night pic so you can see it working.
Hopefully this will be helpfull to someone.
Good luck