I am currently looking at a couple of used '11 and '12 QX's. I am torn between the 20" and 22" wheels. I love the look of the 22's, but what is the tire life like on them? Are you getting less than 40k? I see the price is about $1k to replace the 22's so if wear is that much different I might just sway over to the 20" models and hopefully not have to replace as often.