*shameful sale plug* If you like Borla, look into SSS Adrenaline or Terminator. Same thing. I liked Borla ATAK, but it was stupid expensive, so I ordered SSS Terminators for $299, sounded the same. I even talked with another 3v guy with the real thing, couldn't tell our exhaust apart. Best of all, made in USA from Texas. Just trying to save you some cash if you want borla sound without the borla Price. Other than that, love it. The only issue I had with the s197 GT500s is they do shelby as one little word. Looks so much better spread out across the rear. But a sexy car!!! And I am not certain but I believe the sequentials are a factory thing. I've never seen a shelby without them.