It is same with OM617 pump as it is with OM603, but 617 has only 5 elements to deliver the fuel, 603 has six, and therefore it can deliver more power.

Compress ratio shouldn't be touched, it will worsen the engine power before boost is up, and at cold weather the car won't start.

We are using stock pistons head and all, just change everyhting that is worn out. We are driving with 2-2,4 bars, using mostly Holset HX40 (60 / 65 mm). Forget all hybrids, they are for gasoline cars. Diesel has much bigger wolume of exhaust gasses and it needs bigger turbine. Hybrids have big compressor, but at the same time you increase the exhaust pressure.

What really makes superturbos work is the big turbo (big turbine) that allos the engine to breath. Also IC is very important.

You can use the stock exhaust pipe, but it is not enough for more over 200 hp, I had stock pipe for a week with about 350 hp and it is not good for the engine, it also increases the pressure unnecessarely. I made this pipe myself, 3.5" stainless steel and self made silencer too. Flows more than enough.

In the first version I used the stock exhaust manifold, but it made the turbo (Schwitzer S2B, 50/60 mm) to wake up little late, It could have been better with ALDA adjustment, but I never did that. Soon I installed hand made manifold and HX40 and oh man, that turbo has sweet sound. My wife said the first time in soft acceleration when turbo started to give little boost that it sounded like turbine from Boeing airplane, and she is right.

Pumps can really be modified here, no problem, and possibly my good friend (has that white s*itty looking W124 in one of those video called "liukasta" acceleratind, 433 hp) has a friend that travels lot between Finland and US, this friend can maybe help with transportation....

By the way, that same white W124 had a competition with Ferrari Testarossa, guess who won every time