I frequently see both those cars, Mustang belongs to Marion County Sheriffs. I was cruising on I-5 SB going 2 over in the middle lane while multiple cars were passing me when I spotted a white Mustang flying up from behind. Decided I would get over a little earlier than planned (semi-truck ahead) to bring this guy's speed down about 60 MPH. Noticed it was a Sheriff when he nearly ran into my bumper, pretty sure he was going to sneak up on a SUV that blew by me. Never turned his lights on, but he was visibly pissed and took the next exit.
I got fooled by a plain white F150 on 26WB about 15 miles from Cannon Beach last summer, have to be extra careful these days (although he did let me slide with a warning since he didn't have an exact speed, a very courteous office).
'08 135i - Alpine/Black, BMW Performance