It could be normal. My '03 Malibu has a good deal of annoying suspension-related noises too. Others in the Malibu NG complain about the same thing. Like you, I came over to GM from 16 years of buying Chrysler products. I did so to stay with a US product after Daimler bought Chrysler making Chrysler German owned now...not from any problem with the product. The added annoyances of the level of overall noise with the GM product I bought though took some getting used to...not sure I am used to it yet. GMs silly answer...make the radio volume level automatically increase with greater speed. Seems to me it would have been easier/cheaper just to make the car quieter in the 1st place since the competition seems to be able to do it. What doesn't help is that my wife refused to change, so when ever I need to borrow her '03 Stratus she recently bought, is soooo smooth and quiet in comparison I start back at ground zero when I get back into the Malibu again!!! :-(
I would have the dealer (or your mechanic) check things out just to make sure though.