I could not bring myself to extract a perfectly good set of AC Iridium's in new condition. With coil-on-plug I see no way any other plug is going to fire any stronger than an AC iridium tip plug.

If the plug you're talking about is rated for the OE heat range, the only explanation I can think of for any possible power change would be if the Autolite plug tends to be slightly colder even though the heat range spec is supposed to match OE, and then it would have to be that the factory AC plugs are running slightly hot and causing some minor ping causing the ECM to pull a degree or few of timing here and there in the rpm band. Which would mean if the Autolites are a little colder they eliminate the ping and the ECM doesn't pull timing. Has to be that, seriously doubt its anything to do with the actual spark kernel. And this assumes there is an actual power difference between the two that can be verified on something other than the old butt dyno

 

I like these. Maybe they could become a supporting vendor?

Spark Plugs

 

I believe that many here have already installed one of these:

Butt Dyno

For those who believe in back pressure

This company offers many great products!!

 

I do not understand why some brands of plugs work good in some engines but not in others-but it will known throughout the industry. For example, Spitfire works well for some applications but poor in others. When I had my Saturn, the NGK plug was recommended by most.

 

The Pulstar plugs with a built-in capacitor look interesting but they currently throw a Check Engine light in the HHR.I was told that a fix is in the works.
I have the AirAid CAI and Magnaflow muffler on my 2.4l HHR.This didn't do much for performance until I went to Vector Performance in Detroit to get the car's ECU flashed on their Mustang dyno.Before the tune (with my mods) the A/F was all over the place.After it was worked on the A/F was a flat line across the powerband.
I wanted every day performance so my tune was for more torque.Now I have 150 ft/lbs from 3800 rpm to 5000 rpm (max torque 155@4300 rpm).If you're planning on racing (more HP) they'll tune to suit your needs.My max hp is 145.2@5700 rpm after the tune.
The 'dyno 1/4 mile' is 15.845 secs @ 86.019 mph- before the tune it was 16.37 secs @ 84.136 mph.
This car is not going to be a rocket with just a CAI and muffler! But an ECU flash does make a big difference for the everyday driver.
More Power (turbo,cams,header etc.) = LOTS MORE MONEY

 

Hey HHRRANGE what about that header you bought,have you installed it yet.

 

 

I'm not sure if my BUTT DYNO is malfunctioning or not but it definitely has BACK PRESSURE from time to time.

 

Lol

 

The performance stats you have seem close to mine. I have a Tunetime tune, CGS intake, IMCO muffler, and Autolite plugs. In less than optimal conditions (slightly curved on ramp to highway with slight incline up) and a lot of wheelspin, my G-Tech gave me a 15.9 quatermile time.