I would think there is some sort of safe guards that GM incorporated into the program. They wouldn't be selling any upgrade (that allowed you original factory coverage) that would have the chance of blowing up a bunch of engines.
Me. I'm an old school, mechanical wrench turner. I'm not well schooled in all the modern computer controlled cars and programming.
I got the GMTU back when my SS still had the factory warranty. I chose the GM tune because of being able to retain that warranty.
And. The extra 30 hp and 55 lbs torque.

 

ZZP gets great reviews on the facebook pages. Never read anything bad. The seem to specialize in Ecotecs and have reputation for good support. They have a dyno. I expect to do a mild tune on my SS manual and while I find the GM tune appealing, it seems there are options that cost less for similar results.

If ZZP in Grand Rapids MI is GUD, at the other end of the country is a similar shop, RPM Motorsports in Mesa, AZ. They offer some impressive looking hardware. I know less about them.
https://www.rpm-motorsports.com/stor...formance-parts

Both shops sell the MAP sensors you need for the GM and most other tunes.

 

Hello RBodeman,
I did the GMTU turbo upgrade. I bought the GM kit and installed it myself. Drove it the to dealer 7 miles away and stayed out of boost.and had them flash the ECM.
Then I went and tried the Trifecta custom tune. They have what is called a stealth tune which allows you to switch between files without flashing with the push of a button of your choice in the cabin.
I was one of the last guys to get the automatic trans tune (shift points get tighten up) They no longer support autos and doubled the price on their tunes. I did get 4 tunes from them. 93 gas tune, E47 mix, always on and stealth (switchable) for one price.

I will be trying the ZZP HP tune next.

So far Ive bought many bolt ons from ZZ Performance. 1-CAT down pipe and turbo charge pipes. Very happy with their quality products and customer service.

 

I've read a couple Cobalt owner reviews about it and they're pretty happy about it, nothing spectacular but its pretty good for a canned tune. Some people reported their fuel air ratios could have been better... But again... Canned tune so what do you expect?

For $200, sounds worth it, I'm considering it myself soon.

 

When I first purchased my '08 HHR SS, I got it used with 50,000 miles on it. It was bone stock back then. But like many, I had a desire for a bit more. I initially went with the ZZP parts with just a cold air intake. I felt they had quality parts at a fair price.

As you may have read in other SS posts, the 2008 blocks had the potential for a manufacturing defect. At 130,000 miles, mine gave up. With timing being an issue, I was amazed I could get a new long block shipped to my door from ZZP for $2K at the time, so I went that route. Since I was doing the engine replacement, I jumped in with both feet and got the intercooler and piping upgrades, ECM and TCM tunes, and complete SS exhaust.

The only thing I would do differently after doing all of this is go with the exhaust WITH resonator. Although the delete option allows the turbo to spool quickly, the droning noise gets old for a daily driver.

I did have an irritating issue for quite some time, which I thought was a tuning issue, but turned out to be a bad HPFP. After I replaced that, all is good. The power is incredible and ZZP was great helping me by looking at my data files.

The only other thing on my radar is to schedule a dyno tune with ZZP since they are only 3 hours away from me.

Having added these mods, to me, it seems the best way to go, regarding bang for the buck, would be the MAP sensor replacements along with a tune. After that, a CAI or just filter would be good.

 

My experiences with ZZP are very good (ECM tune for a stock 2.4): very fast response times and knowledgeable.

On the other hand, my experience with the Mesa based shop (mentioned above) is downright bad: took them always a couple of weeks to respond and after we ran into a rev hang issue which they weren't able to resolve, they stopped responding altogether. That's why I went to ZZP, who solved the issue.

 

Highly recommend ZZP tune. Purchase the upgraded MAP sensors from them, then with your HP tuners you can upload the tune and then logs so they can dial it in for your car. They are awesome to work with, very responsive and knowledgeable.