Here's a pic of the harness-it includes (2) relays for each door and each door has its own integrated control harness which splices in-between your switch and window lift motor-all the connections are made on the door-no cluttering up of the underdash to add this. The relays are HD commercial grade and are rated at 250,000 cycles so most likely you'll never have to replace one and are rated at 40A each.
The other nice things are that these allow you to remove the door without messing with pulling the switch through the door grommet and the relay bank will mount nice and stealthy right underneath your armrest base bracket on the door shell....that way, the molded door panel acts as a cover once you re-install it.
The point of this is to extend the life of the window switch and provide less voltage drop by allowing the relay to carry the load instead of the switch-aiding in allowing the windows to operate more quickly.
All the connections are soldered, heatshrinked and the wiring is j1128 spec Delphi automotive crosslink wire which is rated up to 257F and meets/exceeds OEM specifications, so you know this isn't a cheap parts store wire harness. Relays are a Bosch style but again, these are commercial grade and last 4X what a parts store Chinese one will-and, they have built-in tamping diodes as well. Very nice, quality harness kit.
I have 2 kits for 4-doors as well if anybody is interested....those are $179 ea. Again-these mount behind each door panel and take about 10 min. each to install with basic hand tools and a quality crimp tool-soldering the crimp connections you have to perform is recommended but not required. Let me know if you have any other questions!