I agree with what others said. When I was looking at X5M I stumbled upon a pdf that stated that engine lifespan only starts to shorten starting from 750whp for X5M with S63TU engine. Our N63TU is a bit weaker than S63TU, but on a level of Stage 1 that tops 530whp (max so far) - I think we are on a safer side.
BTW Bpc build a S63TU with only upgraded parts been sleeves, pistons and H-Beam rods that dyno 1500+whp - now that is something I want one day. This is their M5 with just 1026+rwhp
https://www.bilibili.com/video/av18297161/