The waterpump I installed is made by LASO. I called the Parts Shop (mercedesshop) and this is what Phil offered me when I asked for a replacement water pump.
It makes sense that aftermarket parts are often not manufactured to the MB tolerances nor quality level. I wasn't offered an original Mercedes water pump or a rebuild, so it never occured to me. I asked about rebuilds, which Phil didn't recommend. I've installed a rebuilt water pump in my 928 S4, but they are a bit simpler in construction than the MB's.
I'm a bit curious about the impeller blades being of a different shape, and how this leads you to state the water circulation will be worse as a result.
I replaced the return hose to the engine block, but not the other three hoses. While observations aren't the best methods to determine their condition, the others appeared to be in good shape, and I figured they would last until the next coolant change.
The coolant has been changed regularly on the car per the service records.
95' E320 (95,000 mi)
88' 928S4 (81,000 mi)
96' Ford Contour (139,000 mi)
86' Jeep Grand Wagoneer (126,000 mi)