Has anyone change just the muffer on an LLY? Leaving the the cat. Any noticable sound difference? Egt's lowered ect. N.H. is going to emission testing and dont want to get rid of cat. Thanks

I put in a straight pipe where the muffler was and noticed a little more noise and nothing on egt. I then put a 4" system on it with no cat. Loved the sound, egts dropped about 100 to 125 degrees, but fuel mileage dropped also and it set codes. Put stock exhaust back on with LB7 front pipe, no cat. A little louder than stock, no codes, and about 75 degree drop in egt. MPG about the same as stock. Thats where I stayed with both trucks.

I changed the muffler on my 05. A more efficient muffler, sounds the same, no louder. Added Predator at 65 hp,.

Save yourself some bucks for other things and leave her stock.

Save yourself some bucks for other things and leave her stock.
this is what I ended up doing. Threw codes and also they are starting emissions here in Texas so no can do. Use the money for a tuner

The muffler I changed to only cost 100 bucks. Pro Flow muffler. I do not intend to change the the rest of the exhaust system. I don't think it's worth the 6 to 8 hundred bucks for the increase from 3.5 to 4" exhaust.

i have a 4" mbrp muffler thats never been used if your interested.....