I know that the HHR'S have 3 primary suspension options;
Soft ride/touring,
Sport Tuned,
and the SS model suspension.

So what exactly are the diffferences? (parts wise)

 

Springs & shocks ?

 

well duh............
I knew that, thus I wrote "exactly".
Let's try again;
So are 3 different shocks used? Are 3 different front strutts used? I'm certain that 3 different sets of springs are used.
If shocks and strutts are shared between models, which are shared on what models?

 

Crooz,you can't get an EXACT answer.That would involve obtaining the durometer differences in bushing hardness,if any,which GM doesn't provide.But springs are shared between standard and sport suspension while they are different for the SS.The struts are different for all 3 levels.

 

I may be mistaken, but aren't the sway bars F/R larger in the SS also???

 

Yeah,the front bar is bigger on an SS.There is no separate rear bar on either version.There may be a beam stiffener welded into the SS rear axle beam.

 

Correct. That is what the TTR swaybar kind of recesses into as it spans left to right for ground clearance.

 

OK, now we're getting somewhere...
To date we have learned that:
Standard & Sports models have the same springs, but different front struts.
The SS has yet another Spring & front strut combo.

I have also heard that the only difference between Standard & Sports Tuned is the front Strutts? I would have thought there was more to it than that.
So what about the rear shocks on all models?

 

For the HHR and Cobalt there are three suspension RPO codes, FE1, FE3, FE5.
As far as I know the "sport tuned" FE3 suspension includes gas-charged shocks and struts while the base FE1 does not. I thought the springs were also slightly lower and stiffer, but I could be wrong about that.
The FE5 (SS) has its own shocks, struts and springs that are lower and stiffer than the FE3. Ride height is comparable to the Eibach Pro-kit, about 1.5-2.0 inches lower than FE1. I thought the SS also came with a rear anti-sway bar, but an SS owner would know better.

 

FE5 springs don't have that much drop (in hhr's anyway). It's more like 1/2'' in the front and 3/4'' in the back.