I reserched a bit and made a smal Graphic for my better understanding wich Cables and Mods are common:

NTSC:
1. As i understand, the VGA-Component-Mod ist the best quality for NTSC-Konsoles but is just working with monitors (Progressive Scan)
2. just the Component Cable (Progressive Scan)
3.D-Terminal-Cable
PAL
1. Component-Cable (without Progressive Scan)?!
2. Scart-RGB?!
Now my Questions:
1. Is something wrong?
2.Can D-Terminal-Cable enable Progressive Scan?
->If so, why would you make an Scart-RGB-Mod wich disable the Progressive Scan?
3. Is it possible for an "PAL-CUBE" to use Progressive Scan if u get like a region mod + NTSC Games?