I inquired about the prices at the Bosch Service center.
Standard nozzle: €77.
Nozzle including NHG: 145 Euros.
In addition to that, there's a 16% VAT, so the total comes to €436.16!
Do you know of any cheaper sources? Maybe in the Munich area. My old car (223,000 km) is also starting to smoke quite a bit, and the emissions test is due next summer.
So, I always buy the nozzles through my parts supplier, who sources them from Bosch. Of course, he doesn't pay the Bosch list price, but gets a dealer discount and then offers me a price.