Wait. "I recently noted that exhaust smell when the car in front of you floors it."
To be clear, you mean when alone, you are smelling a similar smell in your Hellcat?
Exhaust leak no ifs, ands, or buts.
To verify, roll down your windows only about 2" and turn off your ventilation system. Then repeat behavior that led to it. It should make the smell worse. In FACT, do that AND make sure one of the rear seats is folded down.
That is the lowest-pressure zone of the greenhouse, right where the air sideways-ski-jumps off the sides of the windshield, so you are creating a suction that is affecting all parts of your passenger compartment surfaces, which will draw in even MORE of the leaking exhaust.
If it gets worse, then it is obviously the leak in the exhaust system we already know it is, but it reinforces it. If you hear a tick-tick-tick-tick from the engine compartment, it's a header flange leak or one of the pipes is cracked, which is unlikely. It's really a psssht-psssht-psssht but it can sound like a tick which can be confusing.
If it smells like exhaust, it most likely IS exhaust. Anything that clogs the exhaust system, such as a smashed-up catalyst, can make any leak UPSTREAM of that worse.
To pinpoint it, let your car get nice and cold (this is assuming leak doesn't vanish on cooldown) and slather plenty of very, very, very soapy water (Ivory or Dawn make great bubbles) on your exhaust system, then have someone start it up very briefly and watch for bubbles. Repeat as you head rearward starting at front, as the front will get the hottest the fastest. You need a lift for this or jack it up underneaf.
