Wife has a 2021 model 3, got the tesla offer activation kit with the rear speakers.
Overall a very easy install after watching the install video. Rear speakers were the trickiest part.
Overall can definitely tell a substantial difference in the sound quality. Door woofers sound the same. To show my wife the difference, I would unplug and replug the rear and the front speakers for comparison and definitely a buy. I have the model y and she was bummed about the difference between mine and hers but she is happy now!