Try this also. Run the car until the tank reserve light comes on. Get 2 bottles of injector cleaner and 2 bottles of dry gas. Dump all 4 into the tank and fill it up. Did you actually replace the injectors or just the fuel distributor. Remember those vacuum lines. If all of this fails to produce any improvement, get it to a benz dealer and get it plugged into a computer and see if it will output any diagnostic fault codes. Also, do you have the correct heat range on the plugs? When replacing the wires, make sure you get a set with resistor tip/shields as part of the assembly. These can fail and cause misfiring..
1987 BMW 325