I have figured out that I want to run the TTi 2.5" X-pipe dual exhaust (with muffler eliminator pipes in place of where you would order mufflers under the rear seats) bolted onto my existing TTi headers/2.5" collectors. This gets me from my existing 2.5" collectors all the way to the rear bumper and I can add the Accurate SS 2.5" R/T tips. Then I can measure the straight section of pipe beside the gas tank and see which length of muffler would best fit the area.

I am thinking that If I use the X-pipe, I might be able to get away with the Magnaflow 6" diameter SS mufflers (14" or 18" long) beside the gas tank (in place of the existing OE style 7" x 18" mufflers). Then if this is still too loud for street driving, then add the Magnaflow 4" diameter SS mufflers under the rear seat (acting resonator)where TTi places the muffler eliminator pipes (18.5" long).

This should give me the straight through 2.5" exhaust and quiet it down for the street while using SS mufflers and SS R/T tips.

Thanks for all of the replies.