Yes. Headers and DP's will interchange between the HHR and Balt

 

https://www.chevyhhr.net/forums/hhr-ss-45/cobalt-dp-29654/


YES for the 5 speed trans, they all interchange.

HHR auto DP is 1" longer, also the HHR auto 1st cat is in a slightly different location & angle.

A 5 speed factory DP in an auto HHR will have the 1st cat slightly rubbing againest the sway bar. And the stock cat-back will rub at the gas tank, unless you add 1" in length of the cat-back in the resonator section of the stock cat-back.
The Magnaflow cat-back will work ok, no adjustment needed.


excellent 'all-you-need-to-know' thread on downpipes.
http://www.cobaltss.net/forums/showthread.php?t=198998

 

The HHR is made in Mexico...

 

So what do i do when i order the DP since it needs to be 1" longer since i'm auto?

 

You have to add an inch in the stock catback in the resonator straight section,
or in the DP you order. You can ask your DP maker to add an inch.

 

So if im doing just the DP i need to ask Modern Performance to add 1inch to the length of their downpipe since i'm automatic?

This seems to be more a pain than it's worth since i can't buy parts that bolt right up, Damn auto

 

Honestly, just make sure you tell them that it's going into an HHR SS w/ an auto tranny when you place your order. It's that simple!! Take a look in my gallery as I have pics of the exhaust install and you can see how the DP fits (well, Hahn's version anyway lol). I knew NOTHING of "shorter or longer" DP's when I ordered mine last year and haven't had any issues with the DP hitting the sway bar (I don't see how that's possible?? but W/E) nor any rubbing up front. Like I said before the only issue I had was with the hanger over the axle slipping off, but I fixed that and haven't had any more issues. My cat back has never rubbed/hit the gas tank either. Just my .02. Like I said, make it clear what it's going into when you order and you should be fine.

Later
Allex