The Cobalt proportioning valve is what most everyone is using, and it works, but it doesn't use the rear tires to their potential.
Now the goblin does stop faster than most any car on the street, so do you need to stop faster? Of course we do. Autocross rocks.
Pros:
- You can use more rear brakes
- Your power brakes won't be quite so powerful (this is an advantage, as the Cobalt power brakes are too powerful) giving you more brake pedal that is useable
Cons:
- the Cobalt uses double flares on the brake lines, and the 260-12627 Wilwood proportioning valve uses bubble flares, so you probably will be loaning out multiple tools from your local auto supply store, and learning new skills.