Interesting read - doesn't mince words about ZD30's

[Plasnart]

Some media blasting businesses use walnut shell fragments to blast so as not to damage the base metal (usually aluminum) of the part to be cleaned/blasted. Dont know about the calibrated bit though...

Agree. But does anyone believe Mr Nissan outsources this procedure for interval servicing of ZD30's? C'mon they're at the limit actually changing filters.