They have slightly diff frames, Shadow has no firing pin block, diff manual safety lever and extended slide stop, trigger curved, overtravel adj screw, a few others. Shadow is worth the price diff.
Yes to all that except the frames. My understanding was that the frame is exactly the same. Can you give more details?
The SP-01 in the picture is a first production run.
The Shadow also seems to have 3 slots in the picatinny rail, while the spo1 has just 2.



























