I believe your anticipation is correct.

 

I have an 08 HHR SS and an 09 G8 GT.
Got a great deal on both,and the same goes now and days,deals are out there.I bought the HHR SS as a work car in March 08 and the G8 as a home car last month.Needed the gas mileage as it was running about $4 a gallon at the time,and I have about an 80 mile commute 1 way every day.
Actually the HHR SS has a higher top speed unless I'm mistaken,but the G8 has real balls and is every bit as fun to drive,its just different.The HHR SS has a bit of WOW factor because you wouldnt believe how much they pulled out of a four cylinder engine.
The G8 is more of a HOLY ****!! type car.
If you are the type to just cruise around,save yourself some money and don't buy either model.However if you like dusting pretty much anything on the highway,the HHR will damn sure suprise most other drivers.If you want solid Gutt grabbing grunt,get the G8.

 

I also had been considering a G8, either or V6 or GT. I even posted on the G8 website forum to get feedback from owners. There were several reasons I picked the HHR SS over the G8:

1) Gas mileage - most owners were reporting that the G8 got nowhere near the EPA estimates, and at the time, gas was almost $4 a gallon.

2) The G8 is a very big car, and I was actually looking to downsize from my GP - as such the HHR is a breeze to park, especially in all the parking garages I need to go into.

3) My local Pontiac was already starting to reduce stock (it went out of business about the time I bought the SS) and the next closest Pontiac dealer was about 30 minutes away - this concerned me since the last two cars I bought were Pontiacs, and one of the major reasons was because I trusted the dealership and they were right around the corner.

4) The G8, even the V6 model, would have cost me significantly more money than the SS. At the time, the dealers were charging over MSRP, even for the V6 model, and there were no incentives available. I think the differential would have been more than $5K.

5) A relatively minor issue, but I was somewhat concerned buying an Australian product - not because of the quality but because the general lack of American mechanics having worked with the vehicles. I realize that the GTOs have also been around a while, but the Holden cars make up a very small percentage of vehicles on American roads.