I bought a new set of needswings exhaust headers for my SLK 32 AMG a few months ago.
Now I'd like to install it - not by myself but a exhaust shop. The boss of the shop thinks the engine has to be taken out - but he is not sure (in this case he might charge for 25 hours of labor).

Has anybody experience in removing the old headers and installing the new. The engine bay of the SLK 32 AMG should be equivalent to the SRT-6.
What are the processual steps?
How much time do you need for each step?