The w210 is actually a piece of cake and you don’t really need ANY electronic from the w210! Use the mechanical pump from your 603 on the 606 and bam it will run and work. The w210 is a really simple car and so are the electronics. Don’t buy a w211 unless you wanna pay someone for a lot of programming and the confusion and mistakes you’ll make.

I promise once the swap starts and into it at some point your car will be going to the scrapyard with the w211 swap. Not worth the time and effort.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k