Go Here:
http://web.mac.com/dakota/Mercedes/Becker.html
and find your Becker model.
There is a security code(AND if we blather on about it here long enough...
Someone will have mercy on us and deliver it or the instructions on how to get
it.)
(To answer your last question: If the 190's radio is the same model Becker...
It'll slide right in and plug up.)