Squeaky Rear Suspension

I'm only at 15K miles and my rear suspension squeaks going over Speed-bumps, gravel or any other less-than-smooth terrain. Sometimes I hear it squeak on the slightest body-roll.

Anyone who hasn't modified their suspension, are you having this problem? I don't want to take it to the dealership again if I don't have to. I'm tired of dealing with them.

[amoretto]

So, I would like to go back to the beginning of this topic. I also have a squeaky sound in the back of my car when I go over bumps and when someone sits in the back. Car is fully functional, official annual check says so. So is there a way to stop this sound: grease, oil, WD40 and where? Does that sound mean that I have to replace some parts? My Aveo is 1997, 100.000 km, 2nd owner.