Wire Harness - simplify - extra gauges

[philooo]

Ok so I see that company like precision chassis works are using Motec pdm30 on their car to control most electrical stuff inside the car, except engine. like wiper, horn ...

I am trying to understand what's the idea behind it? what are they able to remove by doing so ? can they remove all the wiring harness inside the cabin ? and just keep the poem wiring to the engine ? I have been trying to find info on that but no luck..

while looking at the motec website, I found a cool pdf document to their OEM harness replacement to the ECU for their advanced engine management. I don't plan on buying such thing but I see that they document the use of every single cable going to the ECU. Precious information I think. i see in there oil temp, oil pressure and even more cool stuff with the exact wire number... can we use that to tap into and wire some oil temp and pressure gauges ? sorry for the newbie question here I have no idea how the data is transmitted on these cables..

hoping to understand better what's the point of the motel pdm30 and is the poem wiring can be simplified and also tapped into for some oil gauges.