Hi,
Bad idea, they should be a "deadman switch", not automatic closing, you could trap someone in them.
My 2006 Kia Rio, has electric windows and they are fully manual, that way you can't accidentally injure someone.
A lot of the automatic functions in cars these days are interlocked with other systems.
I don't think your CanBus would like other alien devices connected to it.
It sounds like you car has no BMU, Body Management Unit that would take care of the extra bits and let the ECU take care of engine management.
Tom... 
