Is a catalytic converter a common repair in the G6?

My guess is one part failed, then other rusty bolts were broken by the mechanic while trying to get them apart. That is very common and typical on any car, but in my experience from working at a very nice Chrysler dealership, bolts still can be removed easily on a four-year-old car. Chrysler covers things under warranty if they break in the process of performing other warranty repairs. GM is very customer-unfriendly, but I suspect they have the same policy. That is why you weren't asked to pay for any additional parts.

As far as quality of the product, GM vehicles aren't any better or worse than other brands, at least in most respects. Doesn't sound like you had anything out of the ordinary occur and there's no reason to worry. You can expect a lot of generator failures and expensive trips to the dealer to have computers repaired, but that too can happen with other cars.

GM does have a a lot of trouble with injectors, not only that they fail electrically, but that they are not flow-matched at the factory. If one flows more or less than the rest, an incorrect amount of unburned oxygen will show up in the exhaust. Based on the oxygen sensor's readings, more fuel will be commanded by the Engine Computer, but it increases flow equally among all of the cylinders, even those that don't need more. The best way to avoid this is to buy remanufactured injectors because you will get a matched set.

87 bucks is fairly reasonable for a GM injector. When your mechanic buys them and installs them, you will get a warranty for parts and labor to replace them. If you buy them, which is like bringing your own food to a restaurant, and one fails, you will be charged again for the diagnostic time and the time to replace it. You will also have to find and order the replacement again.

$700.00 - 800.00 repair bills every six months are pretty common on newer cars, but it does seem kind of early to have a catalytic converter failure. If the catalyst melted from too much raw fuel and the resulting overheating, the Check Engine light should have been flashing. Is there any chance the converter is still under the emissions system warranty?

Caradiodoc

No it's not common but it does happen with the converter. It's mechanical so it can break. If the dealer will replace it then let them have at it as it won't cure itself.

Your options are replace the converter or fail the inspection. You might want to check an exhaust specialty shop as they often have an aftermarket equivalent for a lot less money than OEM.