Hi everyone.

I need some advice!

I'm going to change my 2008 X5 3.0SD after 260.000km and I'm between M50D and 40D. I really loved it but it's time for an update!
My mechanic told me that M50D has engine problems due to too much power and suggests 40D and add an chip program to get more power!!
I figured that if it's made by Motosport the M50D would be better and most probably it will have bigger brakes and stronger gearbox.
What should I choose?

Thanks in advance!
Rikos