It depends on your comfort level on working with cars. It's one of the easier jobs. This job may be too trivial for the CD manual.

You'll have to remove some plastic parts under the hood access all the connections. Once you have access, it's a matter of splaying out the new harness close to the old one and keeping track of all the connections. On my car the most difficult connector to access was the one that went to the transmission. You need the hands of a 10 year old with the dexterity of a surgeon to get that one without breaking anything.

The spark plug wiring harness is also easy.

As with any job, don't rush it, and it'll come out okay.

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95 E320 Cabriolet, 169K