The exhaust manifold runners collect around the #6 cylinder and terminate in a flange pointing up. A pipe covered with perforated foil connects to the flange and to the turbo at the other end. If the pipe is more than 4" in diameter, it's a trap oxidizer and should be replaced by MB under recall. You can see if MB will sell you a replacement crossover pipe but it'll be at your cost. MB is under obligation to replace that crossover pipe, inspect the turbo and replace if necessary, and replace the downpipe with a pipe with an oxidation catalyst device (looks like a gasser catalytic converter). I highly doubt they will give you the parts at no cost.

Bar is a metric unit of pressure. 2 bar is about 30 psi [corrected, I said 15 psi previously]. My point was that I would be careful about what rubber hose I used as a boost signal line beyond 15 psi. MB used plastic line for a reason

If you turn the big nut, the ALDA will turn with it. The second wrench is to hold flats in the case of the ALDA while you loosen the big nut.

I'm only familiar with the Garrett turbo. To inspect the wastegate flap you have to remove the down pipe then remove the tail housing of the turbo. Not terribly difficult if you soak the nuts and bolts in penetrating oil the day before you begin work. Working on a hot engine should help... loosen bolts, not your skin.

I don't know how a KKK turbo looks. I think it has an external wastegate vs the internal wastegate of the Garrett.

Sixto
87 300SDL