It's a subjective question... And most times, it's a sickness! Once you get more power and drive it, you become used to it, and want more. Yes, HellCat 1kHP is a bit much for the street, but it's legal, so ok. And there's really nothing that can be done for Driver error! The car, like a computer, can only do what you tell it. Lol
So... I'd say with today almost guaranting up to 80-100HP (per cylinder) in an all out street engine is quite good enough. High HP loads like that HellCat are just not sustainable for longevity. So there needs to be balance, that will take it down to the 60-70HP (per cylinder)...
For me, I'm loving my B58 M240iX, and will probably upgrade the cooling system, DP and tune to bump it up between 400-500, not to chase numbers, so wherever the mods take me, and I have a safe tune running, I'll be happy
