Which is it, E420 or 400E? Not that there's a world of difference, but your thread subject mentions E420 and your post says 400E.
I don't think the w124 cars had a strut-type front suspension. I believe it was coil spring & shock arrangement. With that said, I believe you are misreading the Fastlane catalog, and I know it's easy to miss because the menu doesn't specifically say 'front' when you're in the shock absorber page, and the strut assembly page comes up as 'no parts found' for your models(s). When you're shopping for shocks at Fastlane, just go to the shock absorber page. The ones at the top that don't say 'rear' are the ones for the front of the car, and of course the ones listed at the bottom do specify that they are for the rear of the vehicle. So that could be the source of the confusion.
But Bilsteins only. They are the ones that provide the best ride. Might want to try HDs up front for enhanced handling with the weight of the V8, and comforts in the rear to facilitate a comfortable ride. Some owners of old diesels(heavy engines up front) have reported good things about that arrangement in threads I've read in the past.

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