The guy at the muffle shop told me that he can put a 3" pipe from the cat to the muffler, and then a 2.5" pipe from the muffler to the tips. Gonna be the Flowmaster super40 series with 3.5" tips. Is it a good idea for him to change the pipe to 3" ? Should I keep it 2.5" or 2.25" whatever is stock? I have a 2004 4x4 FX4 SuperCab.

 

why go from 2 1/2" to 3" back to 2 1/2/
he probably can't bend 3" for a tailpipe while he an bend 2 1/2' he probably has 3" staright pieces aND THATS WHY HE would run the 3 ' in that section- my .02$

 

So will it harm me or help me ?

 

no harm but really not much benefit- if the tailpipe was lenghtened- it would help keep up the velocity by the static regain methoid of imploding the tubing- 2.5" to 3" to 2.5"
just get a 2 .5" in/out muffler put on

 

Is he going to run one 2.5 inch pipe from the muffler back, or two 2.5 inch ones coming out of the muffler. If he is doin that (SI/DO) go with the 3 inch one before the muffler

 

Yes he's going to do one 3" from the cat to the muffler then dual 2.5" from the muffler back.

 

Id go with the 3" one then.