n55 carbon cleaning

i recently had my n55 335i carbon cleaned with one the local boys here in cpt. car is completely stock i gained about 7kw and 10nm BUT my consumption has dramatically improved i went from 12.8/13.1L per 100km to
11.8...... well worth the money spent
car has 60k on the clock i was surprised by the amount of carbon build up it had...
just thought i'd share