I was also concerned about fitment issues because I wasn't 100% sure the Volvo XC90 wheels would fit my car. Fortuneately, the stars aligned for me in that I had to go to Ohio in May for a Mustang track rental, and Thompson Raceway was within an hour distance from Blackburn Wheels
, in Macedonia, OH. I called ahead and spoke with Becky, who was VERY helpful. We scheduled for me to drive out in my Focus (yes, I took my Focus to a Mustang event!). Once at Blackburn, they allowed me to test fit the wheels I had pre-selected from their inventory. I had picked out 5 wheels to choose from, and went with the first one they pulled from inventory.
Long-story-short, I needed to ensure that not only the offset was correct for the Volvo wheels, but I needed to make sure that the center bore of the Volvo wheel was large enough to go over the Focus wheel hub. I wanted something different in terms of wheel design, and the 6-spoke pattern has really grown on me.