I think most people register them out of state for this reason - Minnesota and Arkansas being the two go-to (also for bypassing vehicle road-readiness inspections...).
I wish I'd known this. Oregon's bi-annual "emissions test" where they hook up the inspection machine to the ODB port and let the car lie to it is absurd. When I first heard about it I assumed they'd put some device on the exhaust. They do not.
I really wish it was tailpipe based. I liked the PA emissions laws where you could improve the efficiency of your vehicle and it would pass. Not so in CA, must be numbers matching and CARB certified parts/combo.