The om 601 (1984 190D) will be lighter and with the 5 speed ,lightweight vehicle will probably perform adequately. No electronics to worry about. The best engine for a "street rod" would likely be the 2.5 turbo from 1987 but not likely to find many of these around. You are into a project that more than a few probably dream about around here. Please post pics/ details if you take this journey.

Kevin
1979 240D
1984 190D