I'm thinking about doing ours at 3K. The dealer will do the first one for free, but they said to bring it in at 7K. I don't want to wait that long, because of what
@sdhow said. I am guessing they will still do one free at 7K and do all the other things. Did I read right the oil is 0w-20w? That does not feel right. The Honda was 5w-20w, but I did 10w-30w. I think it is a way for the car manufacturers to post better mpg.
I have had a couple of 3.8 Grand Prix. When I replaced the bypass, I would flush and replace it with green, thinking DexCool bad. Both of them I replace water pumps and lower intake gaskets. I got rid of them around 250,000 miles. I just got rid of my GXP (Grand Prix) with an LS. I used nothing but DexCool and never coolant system-related parts, except for the belt. It had close to 230,000 miles. Sometimes the guy who makes the product knows what they are doing.
Having said all that, brings me back to what weight oil to use.