If you're sure that your turbo is "going out" (and why do you think so?), just get another one from a junkyard or rebuild the one you have now. There are other turbos that you can install but ultimately, the limitation is the amount of fuel the IP can squirt into the cylinders. More air (via a beefed-up turbo) won't really do much good. Getting the car back on the road is fine but you're not going to get much more performance out of a 617 engine without serious work.

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"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970