I think the black looks good on the bumper trims. I absolutely hate it on the wheel well trim. That would be the only area I would paint.

I agree. One of the reasons I went with the Space Gray, instead of the Vermilion or Platinum Bronze, is that I didn't think the black bumpers and wheel well trim went well with Vermilion or Platinum Bronze. With the Space Gray it seemed to "fit."

If the X5 had painted bumpers and wheel trim, I probably would have gone with the Vermilion.

I would leave it "as-is" cause I saw one done here and it looks like something is wrong.. as if it was dipped into the silver. The black accents gave it more show and made it seems more aggressive.

Leave it as it is. The aero kit was made for that look. If you want the all "silver" look, then wait until the face-lifted bumpers come out and go that route. Will cost a lot of $$$, but looks better all one color too.