I didn't do a cross over, or anything like that, my gas mileage is suffering a little but its worth it with the sound. My O2 sensor is on the pass. side about 18 inches from the head.
The packaging of the mufflers and pipes renders almost NO clearence if you dont follow the exact path that I did. I have had some issues with the setup for about 2-3 weeks. I re-welded and tweaked it to perfection and now it looks and performs well.
The sound is, hmmmm, can you imagine peter solbergs WRC car at full tilt? Also, mix in a V8 rapping. Without the turbo system of course. I drive a nice sweep of county road on the way to work and the corners are marked at 45mph and the speed limit is 55mph, I drop both front windows at 5a.m. and blast through the corners all the way to work. In a simple way of putting it, I can not get enough of the sound.
I will post pics and a short video clip tomorrow,
Ben