2004-2007 CTS-V Toe Rod Kit, BMR

As you can tell by this comparison of the OE toe rod vs. BMR's heavy duty replacements - there is no comparison. 
The toe rod is responsible for maintaining toe settings of the the rear wheels similar to tie rod ends on the front end. This ensures that the wheels remain set to a fixed position, not erratically pointing inward or outward under loading. 

The factory rods are made from 1/2" material and use soft rubber bushings at the mounting points. Under load, deflection can cause poor launch stability, inconsistent handling and decreased braking ability.

BMR's toe rods are made from 1" heavy wall DOM and use Teflon lined QA1 rod ends with stainless spacers. Moderate install with no decrease in ride quality.