i would for sure go with the x5M you really can't compare it to the g05 4.0..
ok yea so the g05 has all the latest bells and whistles but they are having huge issues with there software currently. The x5M is on a more stable platform.
I was really wanting the g05 50i but just could not see myself purchasing a 90k car(mental thing). I ended up finding a 18 f15 50i for $62k with 10k miles it was driven by the sales manager. You could get the x5m for now and then upgrade maybe to the m50i in a few years
