First of all, I had no idea that other manufacturers made components for the 850 such as control arms and strut mounts. And now that I do, I still recommend that you go with oe. First of all, the control arms were redesigned a couple years ago. And if Volvo felt the need to offer a redesigned control arm, I'm sure pretty important considerations were made, considerations which I would bet those aftermarket companies did not take into account.

Also, oe parts aren't all that expensive if you can find good sources for them. For example, I have developed a great report with the staff at my dealership, and I know receive what they call the preferred customer discount of 20% off of everything. Hell, they even charge me the lower price whenever there are pricing confusions. Also, they have an annual show and shine/garage sale where everything is atleast 20% off.