I did the same work on my G6 a couple of years ago.
Not a bad job at all compared to other cars I've owned. The quick struts take a good 3 hours off the job.
Be careful tightening the back of the lower control arms, watch the torque as the part you are clamping down on is aluminum.
On my car the mileage was low (60K) but all of the rubber had rotted and fallen off so water got into the joints.
Made the car ride nice afterwards. The only lingering issue I have is one of the strut top plates make a creaking sound when turning, I can live with that.