The Do 17Z concept was a 5 seat pathfinder ship differing from other models in the use of the Bramo 323A radials instead of the D-B engines needed for 109 and 110 aircraft. The Do 17Z-1 was supplanted by the Z-2 in 1939 using Bramo 323P engines with 2-stage superchargers with 1,000 HP for take off and a crew of 4 or 5.
The Z-3 was a recon version with the RB 20/30 cameras in the bomb bay.
The Z-2 performance is similar to the Z-1 and Z-3:
6 MG 15 machine guns were mounted for defense- 2 firing forward, 1 aft above the fuselage, 1 aft below and 1 each in lateral positions. 2,200- lbs of ordnnance could be carried internally.
Empty weight was 11,484 lbs and normal loaded the plane weighed 18,832 lbs. 263 MPH maximum was seen at 16,400 feet with a service ceiling of 26,740 feet. With max bomb load the ship could go 745 miles but 1,860 miles was possible w/o load.