The Saab cables look very similar to the HHR cables. I do notice a marked difference in the rotors in the picture in post#4. And note the caliper is embossed GM, did the OP use his HHR SS calipers in the Saab brackets???

 

Those are not HHR SS calipers in post #4.

 

I think you are right Steve, he seems to be saying he changed to larger rotors not calipers.

 

If only I could get to see the calipers and compare them and see the differences! What looks similar or dissimilar in pictures isn't worth a hill of beans when you go to bolt them up and they didn't fit!!!

 

Delta was common, but not with Saab. Epsilon was the 9-3, Malibu, G6, Aura, etc. Delta was Cobalt, Ion, G5, and Astra. There are things that are common between them, but it's not guaranteed.

Back to the recent question, why would you not be satisfied with the Cobalt SS-TC rotors? Are you afraid of over-heating the rears? Cobalt stuff should fit. You might need an adapter if you change calipers, but it should be easy.

To me, the Saab stuff sounds like a lot of trouble for little or no reward. Saab parts never were cheap. I used to compete in one...

 

I think there is a lot of confusion with regards to the options on the rear discs. Chevy Cobalt SS Brembo package came with a different rear caliper with a vented disc. this rotor is a little bigger but more importantly is vented. please see the below links. the first is the Cobalt SS caliper Brembo option in 2010. the second is a HHR.. I always thought the HHR Brembo package had the vented larger discs in the back.. You can upgrade the caliper and then buy the pads and rotors if you are running the rear axle that already has the disc option..

https://www.rockauto.com/info/314/172-2510_Primary.jpg

https://www.rockauto.com/info/314/18R2217_Primary.jpg