See posts #5 & 7 in the thread in link below for what I change when doing this job. Mechanics who are experienced love these jobs because they pay so well. I have a friend who owns an MB shop and and one of his guys has done over 100 of these jobs. He can do the entire job, on a 124, in 8 hours.

http://www.peachparts.com/shopforum/showthread.php?t=152840&highlight=evaporator