Congratulations on your new F10 - what a journey! Thanks for all of the pics - always interesting to see! Even though you had a terrible experience with the 740i Sport... man, I still love the looks of that car, and yours looked GREAT!
Several times I thought about picking one up, but I could never force myself away from the smaller 3-series platform. The F10 550 to me is a nice "modern" version of the E38 740 given that today's 5 series are close in size and 7 series today are like battleships... no resemblance to the sportier platform of yesteryear for me.
You're right - the M door sills (have them in my car) are not illuminated. They just have an "M" logo on them. They look quite nice.
I believe the pre-LCI 550's N63 also used the piezo injectors found on the N54 (your 08 535); so, do expect that may be an issue you deal with at some point. They replaced these on the LCI N63Tu with the same Bosch injectors now found on the N55 and N20.
Again, congratulations on the purchase - I hope this one goes down in the books as one of your better 5's! Post some pics when you can, and enjoy!