You certainly are right on both counts. The Hellcat is 200 to 300 lbs heavier then the Challenger R/T 6.4 Scat Pack, which is your enemy on a road course track - even though the Hellcat has a "competition" suspension. There isn't much doubt that you will be smiling when you step on the "loud peddle" at a stop light - unless you are thinking about the cost of the rear tires
I have the SRT 392 (6.4 Challenger with adjustable suspension, multiple engine/transmission tunes etc.). I suspect it will outperform the R/T on a road course.