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The power window boosters are basically that circuit but with potted solid state relays.

probably....I read he's grounding to the door which reduces the wire run length but puts power through the hinge I guess?

Well clearly you're capable of running a dedicated ground, which is obviously a better idea than grounding through the door metal. Rodney is a great bracket maker, but he's not an engineer.

The little solid state window accelerator really boxes they sell aren't really going to solve the problem either as the power still goes through the switch.

the right answer is the switch controlling power relays so the switch is out of the power circuit completely and the power wires get shorter.

I thought that was the definition of a window accelerator? The whole purpose of the device is to take the switch resistance out of the motor power circuit.

How They Work

Typically the single biggest reason Ferrari windows from these years do not work well is because the existing electric window wiring harness does not provide a good ground to the electric window motors. The way the Ferrari electric window system works is when you push the button to go up one wire is positive 12 volts and the other wire is the ground. When you push the button to go down the polarity in these two wires is reversed. The opposite wire becomes the positive 12 volts and the other wire becomes the ground. Although there can be voltage losses in the wiring harness, switch and any connections along the way - providing a better ground will significantly improve the speed at which the windows will move. This box provides an improved ground making the window motors work much better as they will now receive more voltage and amperage. There is no added burden on the stock wiring harness. There are no detrimental effects to the stock wiring system or switches. This box senses which wire is hot and automatically makes the other wire become the ground and it directs that wire directly to the door frame. These are not always a cure-all for slow windows. You may have other problems like old dried up grease in the window lift assembly or marginal connections in the rest of the electric wiring system. This kit will not correct those types of problems. In most if not all cases the speed of the windows will increase dramatically.

It should be...but that is not what the product you linked is or does. It takes power from the switch but redirects the ground to the door frame....which could be run as a separate wire but isn't I'm sure in the name of easy install. I'm sure they make it better and its a hidden, reversible, DIY friendly alteration so the purists don't hate it.....but its not ideal.