2 1/2" or 3"

id go 3", i just built a new 3" system for my dart. made a 3 1/2" x pipe to match the collectors, reduced it to 3" before the mufflers dynomx ultraflows and a twister muffler on the tailpipe hopefully keep it sort of quiet inside. ive seen plenty of cars with the tti 3" systems they fit real nice but expensive. i like to build my own. im not sure what size im going to go on my duster with the 400.