Obtain the following items.
Clean rags
10-12" adjustable wrench
WD40, Marvel Mystery Oil or similar.
Small piece of aluminum foil

To remove a BMW D50 Direct Injection Injector (others are similar)
do as follows:
1. Remove primary input fuel line from the top of the injector. X3
2. Loosen the other end of the tubing at the fuel pump but do NOT remove. X3
3. Take care...loosen completely the nut retaining the fuel return line on the side. Note the sadwich of parts...and the small copper washers that want to fall away into the deep of the bilge. I used a small piece of aluminum foil as a catch basin under each fuel return line as I removed the bolt allowing the small parts to fall into the catch basin of foil.
4. Remove two retaining nuts and washers from the injector hold-down assembly. X6
5. Lift off retainer and set aside. X3
6. Squirt a small amt of oil to the base of where the injector disappears into the engine block.
7. Remove the spacer from the injector body. X3
8. Drop the injector retainer back onto the injector body.
9. Reinstall the fuel line onto the top of the injector about two-3 turns...no more. (not tight!)
10. Now use the injector retainer as a hammer against the nut to break the injector free of the block. (One finger hammer) Note the threaded section of the holddown bolts...the injector will come up until the injector "hammer" retainer appears about LEVEL with the top of the bolts.
11. Remove the injector (hammer) holddown and turn the injector body gently but firmly a little back and forth (1/8th CCW-CW)with the crescent wrench...lift as you do this and squirt more oil between the block and the injector until it's loose enough to remove from the block. X3

One tough little job but it can be done.