The 3.2L in the Rodeo is very similar to the 3.5L in the Trooper, so I would think muffler advice would be applicable to both, FWIW. As you probably have read, I have the 17748 Dynomax Super Turbo and continue to be happy with it...probably the deepest tone a middlin' size V6 is going to achieve.

However, I haven't tried the Flowmaster. I think Hudson Thompson was going to go with the Flowmaster, maybe he can comment unless it hasn't happened yet.

As far as fitment, the 17748 has a fairly long 20" body, plus inlet/outlet. Go here for dimensions:

http://www.dynomax.com/documents/muffler_general_specs.pdf

You will just have to measure the available area yourself. There was plenty of room for it under my Trooper...also you will need to find an experienced exhaust guy who does custom work. The guy who did mine bent all the pipe by eye, no measurements.