I have the Tesla chains for my X, and have used them a bit. Work well, but make sure you read the instructions - not intuitive to install, at least to me. Getting the plastic nut cover off the wheel can be difficult. You want to practice or get a tool to help you before you are in the blizzard. Small slip joint pliers work if they are thin, or a pair of flat blade screw drivers.
Chains should always go on the rear wheels. Always. If installed on the front, the car is likely to spin out of control. If in tough conditions or on a front wheel drive car, one could put them on all four wheels, but never front only.