2015 M235 w/muffler delete

[diamondtron24]

Hello All.

I'm looking to purchase a new to me 2015 M235. The car is in great shape with 48k miles. I'm a Portlander and the car I'm considering is being sold in WA. I was told it has a muffler delete. (No check engine lights on etc) The car still has the rest of the exhaust and emissions system. Now my question is, the law in Oregon seems iffy on muffler deletes. The interwebz claim both that a muffler is required for DEQ, while other sites claim it's fine as long as the emissions are OK and the noise doesn't exceed 91Db.
Does anyone know for sure if a muffler is required to DEQ in Oregon? Multnomah county to be specific.
And If so, how much would installing a muffler cost? Assuming it's just behind the axle. Also can anyone recommend a good shop in Portland to get this done at?

I've priced out the OEM replacement at 600 dollars. Assuming I got that, (Or maybe a performance muffler) How much would that installation be? I could probably do it myself pretty easily as it's probably just bolt on, but i'm concerned about tuning or if it would require some computer work to install without tripping a code.

Thanks for the help! I look forward to reading into these forums more in depth!

[diamondtron24]

Called a local muffler shop. They said deq doesn't care as long as you keep the cats.