I don't think a whole lot of "performance parts" are available for the Mercedes engines in general. There are people out there making ridiculous power out of the Mercedes diesels with the stock bottom end, so I don't understand what it is you're wanting to upgrade there.

For an OM603 pump, you'll need to find a used unit and send it off for upgrade. It certainly isn't something you can just pick up off the shelf. The OM603 injection pumps used 5.5mm injection elements for all models.

Turbo shouldn't be a huge deal to do, as mentioned above visit the Performance Tuning section of this forum, or join the Super Turbo Diesel forum which is dedicated to performance mods, though usually 617 and 603 engines. Supercharger + Turbocharger may be a bit overkill if you actually want the engine to last or do any useful work. If it's a show car, go crazy, but if you want to actually use the thing for anything it might be a good time to make sure your expectations can be met by reality.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]