It's mostly the same engine, the M has a 6spd while the 5.0 has an 8 speed, braking is better on the M but braking is better on the 5.0 vs my 4.4 also so its still a win. I'm not worried about worth in the long term, these will drop like bricks just like any BMW after 10+yrs. My biggest goal right now is simply power output potential since they're similar engines, but a $10k+ price difference.

I've been doing additional reading, we've seen S63's pushing 700hp, but I still have yet to find someone who's tried pushing an N63 to it's limits...likely because it's still a newish powerplant. JCL's link was very helpful. I've joined another forum as well, where I've found this info - BMW N63 Tuning...

I'm quite happy this day with my X5, but my friend BullKatX5 is looking very forward to finally getting her first X5, so it'll be going into good hands of a fellow automotive enthusiast.

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