lando pr,
I've commented on just such a topic somewhere else on this forum about this very thing. The G6 does have common problems. The G6 has a main issue with the steering clunking, mine has it. If you are looking for a vehicle without troubles you will have to spend a bit more money. The G6 is the replacement for the Grand Am (is was originally refered to as the 6st generation Grand AM, hence the name "G6") and as the Grand AM was the G6 is an inexpensive mid sized sports car. Pontiac targeted the "Middle" income consumers and produced the G6. The down fall of any auto maker that targets an income group is the fact that they will have to use less than the best to make the car affordable for the consumer.
So now to answer your question; I would take the car to YOUR machanic and let them check it out. If all seems well buy it. This doesn't mean you won't have issues. You'll have to take the same chance we all do. I personally do not have the issues with the G6 that other folks seem to and to add, the forums I vist Pontiac, Mazda, Honda and Chevy all have the same theme; "My cars fkd up".
Don't sell yourself short because if you do buy the G6 you might start looking for trouble and if you start looking you will more than likely find it. "When in doubt throw it out". I like the G6, I would buy another one; I almost did.
Good LUCK!!