Euro suspension requires differential removal???

I have parts comming from Affalterbach AMG to restore my brand new 01 E55 to Euro suspension and ride height (which on AMG's direction, not only includes springs, but also shocks and front and rear anti-sway bars).
I'm surprised that my local Benz tech says that his book tells him the whole rear differential has to be dropped to do the rear stabalizer ( and that also the front spring will be a sun-of-gun, translation, many hrs). Am I getting the straight poop here? I've talked to others that have done springs alone, or Brabus, and after a couple hrs and align they are on their way. This dealer is saying at least 2 full days of work. GreggT