21" wheels - My factory tires, chords showing after 17,000 miles. Cost, over $2,000 from Tesla. Not sure what they are now as I've never bought factory tires since. Been in Tesla's since 2013. Cheap set of Falken tires. Cost, less than $500 mounted and balanced. 31,000 miles, another $500.
Over 60,000 miles, factory tires - over $6,000. Falken tires - $1,000. Knock on wood, no accidents. No problems in the rain. Cheap tires lasted nearly twice as long, so less inconvenienced too. Everyone has to do what they feel comfortable with. I've been more than happy with my personal choice for me. Not to mention, I liked the sportier look of the tread pattern on the Falkens.