ok so for the last year i have been running with no cats and no problems at all, except that the exhaust is very loud and the local cops have started noticing how loud the truck is..so is it worth it to even put hi flows in? do they really make a difference? or should i get a longer muffler. right now i have a thrush welded muffler about 13" long, 3" tubing from the y pipe, and then dual 2.5 out.

how much more do hi flows flow than just a regular cat? i have had my engine custom dyno tuned. so will insatall any cat of any kind affect the engine enough to have it retuned?

also i still have my old cats and was thinking of taking them to a scrap yard, what is decent price that i should get for them (all 4) could put that cash into hi flows...

 

get 94106's if you do get converters..it will town it down..but not TOO much

and im not sure about if you will have to retune the engine.

i had true dual thrush welded mufflers and 94106's on my 4.6 pretty loud

 

Get the hi-flow cats, that way you can have better low end torque, produce less carbon in the air, be 49 state legal, and the cops can only give you suggestions to change mufflers, or tell you to keep out of the throttle.