I was wondering if any of you know where the speed sense and reverse light wires are for a 2008 Cad STS thanks!!!

Reverse wire is Lt. Green at the BCM.  Pink Plug Pin 2

VSS is only avaialble on some models of the vehicle.  It is Dark Green/White at the EBCM, black 38 pin plug, pin 32 or radio, gray 20 pin plug, pin 20.  The EBCM (Electronic Brake Control Module) is in the lower right front corner of the engine compartment.

This is for reference only.  Proper testing should be done to verify correct wiring before connecting.

Thanks! I ended up going with the GMOS-13 interface. Seems to work well however, I think I sacrificed a little sound quality. Either way, the z140 is an awesome unit. 

Thanks! I ended up going with the GMOS-13 interface. Seems to work well however, I think I sacrificed a little sound quality. Either way, the z140 is an awesome unit. 

You should have done the bypass on the AVIC-z140. It is easy to do and without suffering sound quality.