Yea you might be over the limit, with the LRD and your other mods you have. The only way I know of gettin it tested is being pulled aside from the forest service or better yet to approach them. I stood in line at oregon one year to have mine tested and with the LRD pipe/s as my only mods I just came in under.
To quiet out your blaster (and get a bit more useable power) repack your silencer.
As for testing the DB level, maybe call your local DMV or Highway Patrol.