I just thought I'd post the link to the Revised Code of Washington. A.k.a. the actual law on exhausts.
http://apps.leg.wa.gov/RCW/default.aspx?cite=46.37.390

It basically says that if your car is 1 decibel louder than stock it's illegal. BUT WAIT!

(3) No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise emitted by the engine of such vehicle above that emitted by the muffler originally installed on the vehicle, and it shall be unlawful for any person to operate a motor vehicle not equipped as required by this subsection, or which has been amplified as prohibited by this subsection. A court may dismiss an infraction notice for a violation of this subsection if there is reasonable grounds to believe that the vehicle was not operated in violation of this subsection.

This subsection (3) does not apply to vehicles twenty-five or more years old or to passenger vehicles being operated off the highways in an organized racing or competitive event conducted by a recognized sanctioning body.

If you have any car older than 25 years old you can run straight pipes... Period that's the law and that's why muscle car guys never get harassed. FB owners rejoice! I suggest you keep a copy of this in your car incase you decide to take advantage of the loop hole in the books

 

Well, you still have to obey local noise ordinances, but you won't run afoul of this PARTICULAR law.

Cars 25 years or older are exempt from emissions too...

 

i know that one too! again another reason for FB owners to rejoice. For some reason i forsee a spike in 86FC 7 prices inthe year 2011

 

haha, i just got pulled over 2 weeks ago in my repu because the cop said my exhaust was too loud. i just smiled because i knew he couldnt do any thing. i love the fine print in the laws.

 

If our cars were as loud as the average Harley, the cops would be all over us in a heartbeat. About 90% of the Harley Davidson motorcycles, including brand new ones, and a very high percentage of modern sport bikes have aftermarket exhausts, and they are ALL much louder than the stock exhausts. The sport bikers claim they want the "extra power", but the magazine tests show only a very small increase in power, which the average street rider would never notice. What they really want is that YOSHIMURA sticker on the muffler, so everyone will think they are cool.

The Harley riders are more honest about it - they will tell you they want more noise.
I asked a friend, who is a Japanese bike racer and builds custom exhausts, "Why does every motor vehicle in the state have to have a muffler unless it is a Harley???"

His answer was "When you ride something that stops and turns like a Harley, people need to know you are coming!"