The reason for slow Windows is that the system uses four micro switches to earth out the appropriate side of the motor.
Fit two relays inside the door and use the existing wiring as signal wiring too Work the relays.
But also slow (or even non) operating windows on Shadows can be due to the inadequate gauge of the door wiring.
Thicker gauge wiring can be used.
The rear doors have a healthy supply for the cigar lighters.
The front will need a fat Brown wire. There is enough room to squeeze one through the door thingy.
The four fuses at the top of the fuse panel can be changed to 1 amp. The New fat brown wires connected to the fuse for the rear cigar lighters.
Or maybe the central locking supply in the door could be used for supply.