Originally Posted by 2fast4thelaw

Dont do that. Speakers in the back that far will destroy your front stage. Use the stock locations and some small 3-1/2" speakers and use 300Hz bass blockers. These will give you a nice side fill rather than rear fill and your front stage will remain promenant. Try it, you will be impressed with the results.

The only speaker way back should be your sub.

Run the rear speakers from your deck or head unit and bridge off the back 2 channels on your JL amp and run a nice sub. You will not need that kind of power on the rear speakers. 10 watts would be enough for rear fill.

You will be selling yourself short by not adding a sub. Even a small one that would fit in your spare tire well would make your system sound 10 times better. If you are going this far, why not go just a little further and add some bottom end.