Yes, Indian made Bosch are not that great; try and source original German made Bosch injectors, your car will thank you! One other item, sometime ago, a poster on this forum showed detailed engineering drawings showing how Monarks do not protrude as far into the injection chamber as ORIGINAL DESIGN Bosch injectors. This may be one of or the only reason I experienced nailing using Monarks. That did it for me; I want my car's engine to operate the way Mercedes Benz engineers designed it to operate.