I have installed parking sensors I got from amazon on cars before. It's definite a DIY level project. Not complicated but take a few hours and IS NOT for the fault of heart
. Remember, you'll need to drill the bumper of your car, although most of the kits come with special drill bits that do not require any measuring. Just stick long piece of paper tape across the bumper so the sensors end up on the same height.
The posters above are correct in that you won't see the sensors on the car screen BUT all of the kits come with small speakers that install in the trunk so they are out of the way and you'll hear the beeping as you get closer to an obstacle behind or in front of you AND most kits come with small screens that attach to your dashboard or to your windshield (I recommend the upper left corner of the windshield) and show things like the side the obstacle is on and even the distance to the obstacle.
A kit with everything mentioned above and 4 rear sensors (no front) cost me $40-50 on amazon. A kit with front and rear sensors will be a little more.
I haven't tried installing it on a Tesla but I imagine that the job would be even easier than on most other cars. It's a hatchback so easy to route and hide wires from the back and it has no engine in the front so VERY easy to route the wire from the front sensor.
If you need any help/advice, let me know.
It may be worth it getting a professional to do it for you but do be prepared to pay 10x the cost of the kit for each end of the car. Their prices are pretty high but they have lot more experience