I know that the rod shifter was an improvement on the Taurus SHO, but on the Contour, the cable shifter is an improvement over the rod shifter.
I don't know how hard it would be to convert. Someone that converted from rod to cable posted that it was extremely difficult because the car was never intened for the upgrade and that he would never try it again.
You are welcome to try it if you want, but you would probably be the first. You would end up with a longer throw.
Just remember that by being first, you would be a pioneer. They say the easiest way to recognize a poineer is from the arrows sticking out his back.