My car puts down 436-434, which is by far the most powerful automobile I've driven. I'm going to have it tuned at DTM and be done. Hopefully come in at 450rwhp.
It's a subjective thing involving a lot of variables. For me, 436 in a standard transmission car feels pretty strong, but I'm not a race car driver, amateur or otherwise. Seen plenty of cars put over 500 to the wheels and the owner will say the car has great street manners. I guess it boils down to your skill level and comfort level. Recently saw a ZL1 Camaro put 613 down, pre-tune. That's impressive, and quite frankly too much car for me personally.
Before anyone posts a picture of RMS TITANIC, yes, I'm aware the Challenger platform is a large one. Even so, 450 for a car that gets driven on trips, etc. feels about right to me. A better driver, or at least a more aggressive one, might require more out of a DD. Takes a village.