If you don't have anything done to your truck, the stock exhaust isn't a restriction.

If anything, only need to remove the cat. You can get a cat delete pipe pretty cheap.

I am running a 5 inch turbo back to 4" duals, just because I have plans in the future of 4" true duals from running trips.

Make sure to plan ahead so you are not doing things 2 or 3 times.

i cut my muffler out left the cat, sounds good not to loud, imo do a 4inch exhaust kit with a muffler

after i cut off the muffer keeping the cat on its alittle deeper sound at idle it only get loud when i step in to it and it ony cost me 44 bucks for 36 inch piece of 4 inch pipe i like it :rocking:

Get rid of them both and live a little.

yeah id do both and add an aftermarket muffler. did this with a banks muffler and it sounds good, more growl than stock but not too loud. slight drone pulling load uphill at around 1400 rpm, but still not nearly as bad as my dads 5" mbrp turboback, it does sound good, just way too loud loud for me IMO. also went from mid 17mpg to 20-21mpg all hand calculated:tu: every mpg helps when diesel here is $5.38/gal and climbing. good luck to you and get that silencer ring out too while youre at it so you can hear it :w2:

Exhaust modifications...
 

I have a stock '06, and am considering the cat and muffler delete as well. My newbie questions are:

Do I need to reprogram the computer?
I if don't reprogram, will I get codes, or experience problems down th road?

You shouldnt have any problems, just double check to make sure you dont have any sensors first. I did my 07 except put a banks high flow muffler back on, too loud for me.

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Btw make sure you guys dont have to do smog checks and all that BS before you do it.

remove both and just straight pipe it. it sounds great. i have a 06 megacab. the only thing that i noticed is that i lost mpgs i was gettin 15 to 17, now im getting like 13. its weird everyone says you'll get better mileage i didnt seem to though. and i hand calculate

I get like 14-17 with straight pipe and cat still on.. i think im gonna go with 4 inch turbo back mbrp kit thougj and see if i gain some milage

I have a 2004 with the stock 4" piping with cat cut out to a Magnaflow muffler and I think it sounds really good! Straight was to load for me with my kids in the back seat and I want to take the donkey dick or turn down off the end that was on it when I bought it and put a 6" tip on so i can hear more of the sound out the side. That turn down puts all the sound at the ground and I hate that but it's nice for not putting black soot on my 5th wheel.