Hoser, you're thinking of dual spare tires?
This open space where spare used to be is perfect for dual gas/water 70/30tank, very low center of gravity.
Brett, what happened to your muffler, are you driving with earplugs?
Cheers,
Muffler's still there, it's ahead of the rear axle. Just the rear resonator is lopped off. I didn't notice a difference on the 80 when that got cut off, but then again, that truck is so loud now...
Some people do notice a slight difference in noise, but if you're willing to cut off the rear crossmember, this is usually a small concern.