Mechanically, the CD will be easier to work on. The climate control servo is a PITA to deal with but until you know that it is a problem, you can't assume it is. I would go with the CD if I were to choose between the two.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge