About a month after I bought my '08 I crawled under it with a sawz-all and hacked the mufflers off. I cut just in front of the mufflers and put on some 45 degree elbows pointed at the ground. LOVE IT! Some of my neighbors won't talk to me, others like it, say they feel safer when they hear me come home (the heavily armed gun nut is home, the neighborhood is safe again!). I didn't really notice any performance changes but was told my exhaust temps would go down, which is good. Haven't had any problems with it.
As for the noise, it sounds like a freakin' race car. Nice low "glub glub" at idle, really roars when you stomp on it. Cruising is about the same, still sounds like a school bus. All my friends think it has a really nice tone to it. It certainly is loud though. I'm guessing around 110-120 dB at full throttle. With the windows open, going through a tunnel and punching it, you can feel it in your chest. The tree-hugging, pot smoking, basement dwellers around Minneapolis REALLY hate it. One more reason I love it!
After I lifted my truck it seems quieter in the cab. Less sound reflecting off the pavement. That helped vent the exhaust out too, more air flow under the truck. I don't know if I'm just used to it, or I'm going deaf (probably more than a little of the latter), but it doesn't seem too loud to me anymore. Then again, I'm a Live Sound Audio Engineer (ie. I go to 4-5 concerts a week, love it loud).
Sadly, I will be adding a muffler soon. I just got my Banks Sidewinder in the mail today and will be putting on new exhaust when I install the turbo. Also, I have to have a muffler in order to wheel in the ORV parks here, which is something I've really been looking forward to.
Any suggestions on muffler choice? It can't be loud, but I still want good flow. I know, those don't tend to go together.
Oh yeah and in VA you have to take your vehicle through it forever but the emissions goes away after 25 years though.
