Vehicle speed and Tach are already on the car so thats the sensors you would have to work with... You would need to know what voltage the computer needs to know... example does the E steering computer need higher voltage signals than the stock sensor puts out or lower level. I would say email DVDburn and ask for his advice... He's an electrical wizard with our cars...
I would try and use a steering sensor out of a rogue and fab it fit the Z's steering shaft... That way you know its going to communicate with the E steering computer properly.