Bosch Platinum +4, I think.

I do it more because I think 100k between plugs is too long.

As a general rule, I over maintain my vehicles most would say.

I change my oil (mobile 1) and Mann/Mahle filter every 5k too. $50 twice a year is cheap compared to a new engine.

In the 20+ years of owning almost exclusively German cars I have found that preventative maintenance saves money in the long run.

OEM parts and regular care keeps outrageous car repair bills away. Helps with resale too.

Dickie
00 ML320
06 325i