IIRC the NA 606 uses a fiber -0080 intake gasket. The turbo 606 uses a steel -0180 intake gasket. Either a mistake or someone tried to save $2 list price

Not meaning to rain on anyone’s parade, who knows what else was touched by plan or inadvertently during this job that smoothed the idle?

Sixto
98 E320s sedan and wagon
02 C320 wagon