An 08-10 SRT8 Challenger weighs 4140 with sunroof, kicker and automatic. With a manual, no sunroof or Kicker they weigh 4040'ish. At least mine did stock. But it only weighs 3600 now

and still has full interior, roll cage, ac, nav, etc.
The 11-12's SRT8's picked up a few pounds and tips the scales at a bit over 4200#'s depending on options.
Anyhow, OP should have no problem with the 300C. Just dont get caught at the light because those are very easy to launch.