Yes you can run duals on an 3rd gen. I had a true dual setup with two mufflers and 2.5" piping back on my 03' V8 Mountaineer. Actually done by a Porsche shop that worked on some our past P-cars. Other's have done so as well. Right now I actually had trouble finding a place that would do my 00' V8 Mountianeer, finally found a shop that knows how to bend piping and has done quite a few Explorers/Mountaineers.
I like those tips though, clean looking.