i just straight piped my dmax and i have to say it really is not very loud. i expected a lot louder sound. i don't know why any one would complain about it. as long as i stay under 1800 rpm in town i really don't see much of a difference in sound. but i guess it does get loud when you get on it .

the sound is better jut not that much louder

Not very loud inside, but outside is a different story. Trust Me;)

i don't know why any one would complain about it. as long as i stay under 1800 rpm in town i really don't see much of a difference in sound. but i guess it does get loud when you get on it .

The problem people have with the straight pipe is above the 1800 RPM range that you mentioned, like driving on the expressway. That is where the drone or resonance comes in and can be annoying, especially on long trips. The muffler eliminates this problem and does not restrict the flow. The outside noise is still authoritive and will make any gear head take notice.

Did you cut off the muffler and add a striaght pipe?

I cant find a 3 3/4 or a 4 inch pipe anywhere around here. Any suggestions on where to get one.

Find a Freightliner or other "big rig" shop and they'll have it. Main thing is to make sure you find a muffler shop with a 4" tubing expander, otherwise you'll be doing some redneck engineering to get it to fit. My pipe I bought was the same exact diameter and the shop I did the work at on post didn't have a tubing expander.