I've checked long ago.. my 2LT has no rear sway bar till I installed one..
It had a front one.. post a pic of yours...

 

This quote is from Chevy site...

Touring suspension
The touring suspension, standard on LS and 1LT, includes variable-rate springs and a 19mm front stabilizer bar. It is not available on 2LT.

Tuned sport suspension
The tuned sport suspension, standard and available only on 2LT, includes variable-rate springs and gas-charged shocks with a 22mm stabilizer bar.

 

if there is not rear sway bar then what that bar in the v groove in the back

 

probably to try to keep the " v" bar rigid

 

but if you look at the install pic on page 2 for the aftermarket rear sway bar you do not see a bar and the aftermarket one fits in side the v groove?

 

Yes, ther is a round bar inside the torque tube, it is there to "stiffen" the torque tube but does not work the same as a separate sway bar. The Progress Anti-Sway bar bolts to the "lever" end of the spring pad, and is kept "mechanically" separate from the rest of the torque tube (it does however, fit up inside the tube). This allows it to provide maximum resistance to inside wheel lift. It does work in conjunction with the existing torque tube - and greatly decreases rear end sway.

Ask a couple of members who have already installed them!

Hope it helps,

 

Looking forward to putting mine on! Thanks in advance

 

I finally had a chance to put the car into a few corners (Hard). The handling has increased more than I could have imagined. My HHR is not lowered and the addition of the sway bar is wonderful.

Thank you Progress Tehcnology and SoCal

 

I ordered mine. Should be here in a few days. I had heard that Mike at SoCalHRR is great to work with and I'm here to say that he represents his company well. Thanks Mike

 

ok here is my report.... Tokyo told me that it would not make a difference cause the way the HHR is made in back well i have this to say.... not true

the antisway bar is great- install time 20 min tops and i used ramps and backed up on them, locked the parking brake and blocked the front wheels. carpet runner to lay on,,, all is cool,,, it is only 4 bolts and the 2 bars with the nuts welded on it,,, really easy mod and worth every penny. anyone can do this.

putting it on,,,,pointy side of the bar toward back of car to hold on to it. flat side down,,,
i did the 2 rear bolts first to get it in place and used a small 2x6 that i hammered on the end a little to hold the other side of the bar up while i did the first side... prep makes all easy they say.

i found that you need to put the bolt to the rear on first on both sides and just get it in enough to feel it at the top of the nut. then push the bar at the point up a little and angle it down to make it easier to get the front bolt started. leave it loose

then do the front bolt on the other side... i am a firm believer in snugging all 4 bolts first before you crank on them with a torque wrench. torqued them all to 45 lbs and i put on one drop of locktite to help keep them snug.

NOW driving report
HHR felt taller in the rear so i lowered my seat couple of pumps. also the ride feels lil stiffer now too.

all in all i liked it so i took it to my favorite driving spot,, the clover leaf at 635 and the north toll road.
this is a cool place cause you can go from to another and never leave till you are tired of it
http://maps.google.com/maps?q=Addiso...,0.009742&om=1

i went around all 4 a total of 4 times to really try it and i was averaging 50 to 52mph around the turns and having a blast when no one was on it. yes, 16 turns non stop and just slowing down enough for traffic. last one put me back north on the toll road at 72 when i got back on. all in all it is great

seems to lean less now as well