Are you in the U.S.? Is yours a Euro? This source says only turbo 603's were officially available in the U.S.: Mercedes-Benz OM603 - Wikipedia, the free encyclopedia

The conventional wisdom on adding a turbo to a factory non-turbo engine is not to do it, but some folks have added a turbo successfully. You can probably find more information in the diesel performance section.

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Whoever said there's nothing more expensive than a cheap Mercedes never had a cheap Jaguar.

83 300D Turbo with manual conversion, early W126 vented front rotors and H4 headlights 401,xxx miles
08 Suzuki GSX-R600 M4 Slip-on 26,xxx miles
88 Jaguar XJS V12 94,xxx miles. Work in progress.
99 Mazda Miata 183,xxx miles.