custom resonators?
 

Is this a thing? I have a couple of low frequency drone/bass issues around 1200-2000 RPM where I'm setting off car alarms on cold starts or going slow, usually in in parking garages, and it's pretty obnoxious. Otherwise, I love it: tomei uel/op, stock fp, Perrin 2.5 resonated cb

Anyone familiar with a shop that could help with making a custom resonator to cancel out frequencies (helmholz)? Any other tips to get rid of it?

:cheers:

Have you thought about one of those exhaust muffler valves?
You can put it in front of the muffler that way it can quite it when ever you want.
That's my guess.