My car has been running in the stock configuration for 106,000 miles. The manifold has only been cleaned once. I had it off just a couple weeks ago to replace the shutoff valve, and there was just a light dusting of soot. Definitely not enough to affect performance. Bottom line is that the turbo OM606 just doesn't clog up as much as other engines, so it's really not a big deal.

__________________
Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
Chain Elongation References