I had something similar nearly happen last summer.
I live just outside town in the country a few miles. Before I bought the Stinger I had a prety fun turbo 5.0 mustang (notchback foxbody). I left my neighborhood one morning for work and got on our main road. After the first turn I saw a newer Charger with the hood bulge/intake come up fast on my tail. I couldn't see if it was a hellcat or Scat pack...whatever... It was clear this guy noticed what I was driving and wanted me to notice he had something he was proud of and was right on my tail. I initially wasn't speeding but he was right on my bumper so I gave it a good job and off we went.. The road is 55mph and we probably got up to 80-85 before quickly getting stuck behind slower traffic and nowhere to pass. Anyhow, we get into town and the main strip opens up into more lanes. He pulls up next to me at the light and rolls his window down. At that time I see he's a uniformed cop. He then said, "Looks like that thing runs pretty good". I said "yeah, it's a good time". He then basically replied, "cool!" With a head nod and then light turned green. He proceeded to tear through first and second gear and then make a fast hard left into the police station. I sure as shit wasn't about to race him, off-duty or not, and I left the light like my grandma.