RonandJanet,
If you are getting the badest one, factory spec'd the hellcat charger its faster in top speed than the challenger, but if you are looking for more check out either HHP or Hennessey they have some unreal packages. There is supposed to be a 900+ kit available soon read it was going to be warranty capable, but dealer said it is not, but it is not yet available. under 4k they say, smaller pullies, belt(s), and new ECU pre programmed.
Its a handful for sure, but the fun factor is way up there too. 55mph and give it some gas and dont mean romp it and it will break the tires loose. Not something you would ride around with without the traction control. Drifting would be a non issue. Check out the launch functionality.