Looking very very nice already Nino.
As you mentioned, the machine was pretty filthy. Those pop bumper skirts don't look like they have ever been cleaned. I am guessing that the ball trough was pretty grungey as well - another dirt trap that is overlooked by 'shoppers'.
Black rubbers actually suit some games BUT you must have a few lighter coloured rubbers here and there e.g. flipper rubbers, Cliffy post rubbers to give you an indication of when it is time to give the machine a clean i.e. when the black lines start appearing on the rubbers.
That SW is going to be a damn nice machine when you have finished with it. Looking forward to the next update.