Seattle Tax + Tesla Tax... Besides if you're talking to NWAS and/or Metropolitan you're talking about two of the highest rated shops in the area. At any given time they have millions in customer cars under their care due to their reputations of doing great work.
There is a Northwest Tesla Owners group on Facebook that's pretty active and have had some good recommendations of less-known shops in the area. I remember a couple in Kirkland getting really good reviews recently.
Nick