Well E92 M3 was 414hp vs E60 M5 507hp. That is appx. 91hp difference between the two. I think the new M3 should then at minimum be a 467hp car at least to maintain the gap.
So in conclusion I would be happy with superb a driving dynamics and great steering feel in a 450hp new M3. However, I think I might be a little tiny bit more happy in an M3 that offers everything above but in a 470hp package