Adding new wires?
 

I want to add some wiring from the engine compartment to the DME area of my car for data acquisition and a wideband O2 sensor.

Is there a suggested route to take, or should I just make another hole next to the stock bundle going to the DME? If I pull out the rear seat, is that where the wiring goes through?

Thanks!

If there is already a hole that the DEM harness runs though you may be able to snake something like this
https://www.sparkfun.com/products/10647
or this
Ghost Wire SW-29819 50ft Super Flat Adhesive Speaker Wire - 16AWG 2C, White
around it and avoid having to make a new holes in the chassis. Ribbon cable is typically used in digital equipment (although it has plenty of other applications) if you are planning on running high current through the wire make sure the wires can handle it.