Parada Spec-X on sale $162

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2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
How do you figure that this is cheaper than Tirerack.com?
For me, it is $808 vs $828. Tirerack.com wins by $20.
Though the listing price is higher, tirerack.com has lower S&H and tax.