Did anyone ever figure this out?
I'm curious whether I actually go anything for my $5k other than 20" wheels the bend when you look at them.
If you go visit any car forum you will hear stories about folks bending/cracking wheels with low profile tires. The reality is if you hit large potholes then yes you are more likely to bend a wheel with a low profile tire than you will with a 45-55 size tire. It doesn't matter if it is a Tesla, Corvette, BMW, etc. That said, I have been daily driving performance cars with low profile performance tires on 20" wheels and never had a problem. My Tesla M3P+ with 20"s feels like a Cadillac compared to my Corvette with 20" run-flats. I guess it depends how bad the roads are where you live.
For the $5k difference, you get bigger brakes (rotors, calipers and pads). If you care about better brakes and plan to go aftermarket at some point then plan to spend $4k or more to upgrade them. The 20" wheels fill in the wheel wells a lot better and help the Performance trim look the part. The best part about the wheels are the Michelin PS4 performance tires. If you plan to push the car it will corner and brake better with these tires. The suspension is also lowered close to 1/2". The rest of the stuff is just gingerbread, carbon fiber spoiler, pedal covers.
So, brakes, wheels and tires. That is the main difference. The stabilizier bars seem like they may be different but I can't tell if this is just the difference between an RWD or AWD or AWD and AWD Performance. Could be thicker bars, maybe firmer bushings, etc. See parts list.
If Tesla plans to add some performance stuff down the road (updates to Track Mode, more power, torque bias control, etc.), I would hope the P3+ would be the trim to get it.