It depends on your budget really.
How is you fuel mileage?

You can do a visual inspection to see if the injectors are pitted. You'll most likely need a deep socket, a breaker bar and a pipe (for additional leverage), as well as new injector washers ( about $5 for a set), and possibly new brained fuel hose. Pull each of the injectors and clean them off the tips carefully, if they are heavily pitted/ and original, I would plan on rebuilding them. There is a kit available from a certain Mercedes enthusiast that is DIY for injector rebuilds, otherwise you'll need to find an injector rebuild center, fortunately shipping would be very reasonable.

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Nosce Te Ipsum "Know thyself"