H&Rs will lower the car 1 to 1.5 inches. Spring pads adjust in mm, so it is more for "fine tuning" the height.
I am using Bilstein Sport and the interesting thing is the Bilsteins actually lowered my car even more. (which I am not too thrilled about, so I will probably use a thicker spring pad to "correct" it)
Most of the tuners (AMG included) source from the same manufacturer (Bilstein) so the core of the shock is pretty much the same, it is just valved a little differently thus giving a slight variation in ride characteristic/quality. So, yes, I would have to say it is similar to the E55 shocks even though I have not compared the two set up side by side. The Bilsteins will run you about $450-$500.
I did not change the sway bars.

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1997 E420