I just changed mine with NGK BKR6EQUP's over the weekend. I didn't notice a difference at all. I have 104k and I pulled out Bosch's with BMW on them so I assume they were the originals.

2 weeks ago I changed the fuel filter and damn... night and day performance increase. It feels much smoother and less restricted now, but I still have a problem with it acting very sluggish at times and jerky on-off gas acceleration