Sorry for posting my review so late. Been very busy at work for the last number of weeks.
The P2140 worked great the way I had it config'ed which was to set both main lines to 12v and use a Point of Load for the screen. Main reason for the Point of load was to not have to run another power line all the way to the front of the car.
For startup I used the Dell's start up on power setting in the BIOS, works great so far. For shutdown I took the ACPI signal from the P2140 and using a automotive relay sent a signal to short pins 4/8 of my serial port when I turned the car off. A software shutdown controller then takes the signal and initiates the hibernation. I believe if I soldered the lines on the power button it would also have worked. But I didn't have the luxury of time. The software shutdown method is used by many laptop users on the forums and getting the 5v signal to the serial port from the P2140 was pretty easy.
I am now using the DSX12VD which also works great. Start up and shutdown methods haven't changed. The P2140 is being mated to my old setup (Via M10000/Lilliput 7") for my wife's car. At the time I needed the second power supply they were not in stock so I went with the DSX12VD. Love them both can't go wrong with either one in my opinion.
As time permits I will be posting the new setup in a Lexus GS. My other car will probably share the same Dell with the Lexus when I am finished her overhaul.
Very noticeable difference between the Via setup and the P4 in the Dell can’t say I would turn back.
Hope this helps.