I have replaced the axle's on my E430 4matic last year...this post should help you:

CV axle replacement on 2000 E320 4Matic - Benzworld.org - Mercedes-Benz Discussion Forum

One note - I found that I did not need to separate the tie rod end from the wheel carrier (I believe the WIS instructions tell you to do this). It took a bit of maneuvering but I was able to get it out. That was helpful for me as I don't have the proper ball joint separator and as a result tend to destroy them when they R&R with a hammer/pickle fork.

Also of interest...I ordered re-manufactured axles from CVJ (CVJ Axles - Remanufactured Axles & Power Racks) for around $120 + shipping (plus core charge). I used these because they are genuine mercedes parts that they refurbish to spec; I didn't want to take a chance on an off brand.

They have been in for 6+ months and working great. Others over on benzworld have used them as well with good results. MUCH more economical than the 1300 from the dealership.

PM/post if you have questions.

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE