I've got an '06 S60, and when I'm stopped and then accelerate, I can faintly hear a slight popping and feel kind of a flexing coming from within the engine compartment. I should probably have my motor mounts checked? They were replaced under warranty just over a year ago.

 

I've also got uneven tire wear on my front tires. There's more meat on the driver's side than there is on the passenger side. Could that be bad or worn struts?

 

If you take the car to a suspension shop they should be able to tell you what is bad or worn under there. It can be anything from a worn axle to a bad tie rod end or ball joint. If you jack the car and try to whiggle the wheel up & down then left & right and see if you have any play in the suspension. Report back with any play. It's safest to have the car on jack stands.