The blower motor replacement is an advanced repair. You should only attempt it if you have a good grasp of mechanical knowledge and alot of time on a saturday.
I would suspect that it might take you at least 3 hours.
Our shop charges 2-2.5 hours for this job I think. I don't know where 4 came from.
You should not have to replace the controller at the same time.
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM