The '99 is a W210 chassis, the '95 is a W124 chassis. Since the '95 used the OM606 engine and the '99 did too, there will be no basic mechanical problems getting the block to fit. I don't know about the transmission. The biggest challenge might be fitting the turbocharger and intercooler into the W124 chassis. The OM606 engine in the '95 was normally aspirated so there was a bunch of stuff it didn't have.

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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