I'm in Aurora and need to have this checked. I think it would be good to post the results with my setup as well. I have a feeling I'll be getting the quite core insert and repack my pipe to see how much of a difference this makes. If it doesn't get the db to where I need it I'll certainly be getting the "Q" and posting those results as well. Any suggestions on where to get this tested?

Have I not not searched enough on this and this is a dead question or is no one looking at this post?

I think you can buy a cheap sound meter at radioshack ($30?). Look up how the enduro guys position the meter on one of the enduro websites.

I think Mike is on the right track with this one. What do you need to hit a certain sound level for in Colorado? I wonder if a forest ranger might test it for you if you went in voluntarily and asked to do it???

I used the Radio Shack sound meter on the same setup (i.e. PowerBomb SX and Power Core 4 on my 02 WR250F) - the idle db was 100 1/4 throttle was 110 db (trying to get to around 5K RPM) and peaked/whacked out at around 115 db or something like that If you're using this setup, I don't know what your sound law in Co. is, but I bet that it won't pass any of them

Good luck.