Your garage looks great! Thank you for your business.
Our comment is that certain tire compounds can stain PVC tiles. Colors other than black can posssibly stain, and we don’t offer a tire staining warranty on our Supratiles. We have seen projects on gray floors wher one car side looks great and the other aide (different tire brand) got stains).
Certainly if you want gray go with dark under the vehicles or use parking pads.