I need meaner sound!

Personaly, whatever you do, get them exhaust gasses out from under the vehicle. They are very corrosive, and it WILL accelerate the rate of decay of your vehicle if you leave it dumping under the car for long (months or more, a few days or so wont be critical) also any place that the fumes can penetrate the floor pan or trunk will allow them to find their way into the cockpit, not that it will kill you (although, it could) but it can give you headaches and you might not realize why your getting them. Either side pipes or tail pipes, no dif, just so long as they dump somewhere other than underneath. Also depending on your exhaust you currently have, it is probably blowing hot exhaust on the rear end, just that much more added heat to the fluids, etc. Just my .02 for the day.

Nothing cooler sounding than open headers on a new 12 to 1 big block, WOOT.