Just had the recall completed on my 2016 (07/15 build) 328d wagon. I was a little nervous after reading some of the headaches people have encountered here but I picked the car up today and everything has been fine so far.
Here was my experience:
Bought the car 2 weeks ago from a non-BMW dealer with 85k miles and one previous owner. Discovered there was an open recall, and although the car was not showing any symptoms such as coolant loss, CEL, or exhaust smell, I didn't want to deal with it in the future so I brought it to BMW. I figured at 85k miles the carbon buildup inside the intake and EGR cooler are probably pretty bad so why not get them replaced for free?
They did the inspection, found that the EGR cooler was leaking internally, and ordered the replacement parts which would arrive a week later. When I picked up the car after the inspection I immediately noticed a strong exhaust smell in the engine bay and through the vents, as well as significantly increased turbo noise. My guess is that during the inspection they cracked the EGR cooler piping resulting in an exhaust leak. So I left the car there and the dealer paid for a rental car in the meantime.
Parts arrived on schedule and the repairs were completed. My copy of the repair order didn't show prices but I got a photo of one of the warranty copies showing what was replaced:
I'll report back if there are any follow-up issues, but so far the car seems to accelerate slightly better but who knows, I only drove it for a about a week before taking it in.