Phantom Armada out there somewhere

I made the drive from Las Vegas to L.A. this weekend. There's a 200 mile stretch on the 15.
I am on cruise control 80mph, I see a Tian or Armada inthe rear view mirror closing in on me fast. I pull over to the right lane, and a silver Armada goes flying by me at least 100+. I heard a very weird sound. He pulled off the next offramp north of Bakersfield and I followed him.
Then he pulled back on freeway again. I pulled next to him and floored it, he pulled away from me like no Armada could and when I hit 95mph, he was a good 20 cars lengths ahead of me.
Here's the weird thing.
Car had mfg plates and all stock looking. I had my window half way down and heard something very strange. Sounded like a twin turbo. I'm almost positive. Double high pitched whine with an almost uncorked exhaust. For sure not a supercharger.
Had a straight 4" flat black exhaust out the back.
That's all I could see and hear. Never caught him after that.

There's no way that thing was a stock engine. I'm running a totally stock setup with no load other than me and wife, and he pulled away from me like only a Corvette or 911 could have.

This Armada was crazy fast.

If anyone out there makes Vegas to L.A. runs, keep your eyes open for a Silver Armada that drives like a bat out of hell.

I want to know what he has under the hood.