Tested the Deer Slayer for a bit.
 

The temptation finally got me tonight.. Nice 2.5 straight stretch..nothing in sight.. well it began..

The foot got heavy and away we went for 1/2 mile.
Shut it down at 5,800 rpm @ 115 Mph.... redline for my Trifecta tune is 6,450 rpm
so had a few rpm to go..

how stable is the car at those speeds?

It was smooth, but one tire is slightly off balance... I will think about trying one more time after the new skins hit the Deer Slayer this spring.

So, is the only performance mod you have the Trifecta tune? I would be interested in purchasing if the performance gains were real, and it didnt throw CELs. What do you think the expected power gains are? What does your tune do to the trans, and what have you experienced in gas mileage changes? My car is an 06 2.4 auto. Thanks.

Here is Sticks comments:
Here is one from Stick that was posted in the ChevyHHRWorld Store forum Question and news area, I posted for my Tune and there is more at http://www.trifectaperformance.com/

Hey all, I'm Stick.
Some or most should know me from here, but I'm here to tell about the Trifecta Tune. This is a great deal! If you want to increase performance without having to go through a bunch of mods, do it. I have a CGS intake and Magnaflow exhaust on my 2.4 with a 5-speed. Tom was able to get me the program and cable and all the paperwork/directions to install the tune off my laptop. The whole process took little more than five minutes. The difference is very noticeable. Power was added at the entire bandwidth. I can hit 75 in 4th gear getting onto the highway and passing is a breeze! There is no delay when hitting the gas pedal, just go. All in all a good investment in my honest opinion. Mileage for myself has gone down a degree. From 29 to 27, but, but I am having more fun with it now then ever. I get into the car and hit the gas and enjoy it daily!

My Comments: from this forum
I installed my Trifecta tune in the Deer Slayer today. Did some starts and the delayed timing is gone now, I have a 2.4 Auto. The RPM's went higher than 6,000. The transmission shifts quicker. Kicking into passing gear at 60 Is like go, go, gone.

The tune I was going for was better mileage and a boost for towing my ATV and trailer that weighs 780 lbs.

My HHR is stock as far as intake and exhaust. I filled my tank with gas and will see how the mileage does when I fill again next week. A 55 mph highway drive today before and after the tune on a level stretch bumped the MPG up 2.8 mpg. I will post the average next week. My pre-tune average is 27.6 mpg, this is both highway/city, my round trip to work each day is 64 miles.

Yes I only have the Trifecta Tune, Both my ECM and TCM are tuned, I did not go all out on either tune, They can be more radical if you wanted it. It would most likely need to be data logged and share the file with Vince at Trifecta to make any adjustments.

My TCM is a mild upgrade, I tow small trailers with the ATV mostly.
Expect 10-15 HP for a power gain. My mileage is up a small amount, Throwing CELS has not been a issue with my HHR.

thanks, stick
 

i have asked 2 different times on this forum if trifecta offered a tune for mpg. both times , i got no replies. i have auto so my results would probably be a little different than yours. if you are saying that you can drive your car a little hard and still get 27 mpg , i think that is good. but if that is all you get when driving easy , i think that 27 is not so good. i would like to get 32+mpg at 82mph . maybe i want to much. but i believe it can be done with the right setup.

it has been mentioned here that trifecta will be coming out with a mpg tune.

What engine do you have, You have a auto I see.