Hi folks, I had my configuration for a Performance Model 3 (PM3) in, then downgraded it to Dual Motor. I and likely others here have one day left (during the 3 day change window) to change (back) to Performance. I had it on Performance at first but downgraded to Dual Motor, in part due to the lack of clarity about the Performance brakes. I've just changed it back to PM3 with no Performance Upgrade (PU) option per my analysis below. (Either way, I'm very happy to be ordering a Model 3 and extremely proud of the Tesla team for reaching this point.)
Reason for wanting to order PM3 without PU is to save a bit of money by skipping the spoiler, etc., in PU while buying my own 20 inch wheels with Michelin Pilot Sport 4S tires from Tire Rack for around $3k. I don't need the pedals or spoiler. I don't mind also having the Aero wheels which I'll use for at least road trips.
Comments on some questions from the thread above, plus additional analysis:
1. I configured my car on June 30 in order to capture the free Premium Connectivity (and also to hopefully get the full Federal tax credit before the phase out likely to go to 50% on January 1. It would go to 25% for Q2 2019, and then 0% for Q3 2019 and later). The folks at my Tesla store said that changing the configuration does not change the initial order date, so I keep the Premium Connectivity even if I make configuration changes within the allowed 3 day change window.
2. Tire quality. The Michelin Pilot Sport 4S is currently one of the best street tires available. Tires make a extremely significant difference in performance. They are the only interface with the road and are critically important in how any vehicle performs. For a high performance car, it's very important to get excellent and tires. The 18 or 19 inch wheels with lesser tires will not have the same level or quality of performance as the Pilot Sport 4S. (Currently it is one of the few performance tires available in the right size for 20s on the Model 3; others may arise later.) Tires all also have different subjective feel and response, purely due to engineering differences, and this affects how the car feels and how well the driver can extract maximum performance from the tires. On both objective and subjective aspects, the 4S is excellent. See tire comparisons on Tirerack.com, car magazines, etc., for example.
If you're going to get the Performance Model 3 (or any performance car, TBH) and expect to get maximum performance from it, and/or take it on a race track, you must get the best wheels and tires to be able to get the full performance. No one who is knowledgeable about performance driving, racing, etc., will find this incorrect or even controversial. It isn't.
3. Tire diameter and top speed. All of the Tesla wheel and tire combinations for a given model have nearly identical overall diameter. This is normal practice since suspensions are designed with a particular diameter (within a fairly narrow range) in mind. The smaller wheels have higher profile tires. The larger wheels have lower profile tires. The net result is a similar overall diameter across all. The top speed increase does not come from any significant diameter difference. It's a software unlock.
And no, it's extremely unlikely that any third parties would be able to hack this and unlock it for you. Control of the vehicle firmware is extremely tight, and rightfully so. None of us would want unauthorized changes that could endanger our safety. Very likely hardware encryption prevents unauthorized software or even major configuration changes from running. This is as it should be on any vehicle sold to the public.
Getting PM3 without PU probably means missing out on the top speed upgrade, but top speed isn't useful on most race tracks or most races. Most race tracks are too short to reach top speed. There are few places where top speed is legal. One is the Autobahn or other unlimited speed roads. Another is legal closed road speed events. I plan neither.
4. The rotor size does look much larger on the Performance Model with the factory 20 inch wheels that Elon tweeted. The "teeth" on the rotor hat are possibly for triggering Hall effect (wheel speed) sensors for ABS, or could be a vestigial artifact from their supplier. Larger rotors do improve brake performance for several reasons: more clamping surface area, greater leverage from the larger rotor diameter, and perhaps most importantly for repeated braking from high speeds on a race track, more heat capacity. It's unclear whether the Performance Model without the $5k Performance Upgrade (PU) option includes the larger rotors and possibly upgraded calipers. If the larger rotors fit in the 18 inch wheels, they may be included even if PU is not ordered. If they don't fit, then a Performance Model ordered without PU may not have the larger rotors.
5. The calipers may or may not be the same with or without the PU option. At a minimum PU adds red color. At a maximum, the calipers are physically different in addition to having a red finish. Caliper design can have an effect on performance, but the rotor and pads may be far more important.
If Sasha's analysis at Mountain Pass Performance is correct at
MPP Page Mill 365mm Big Brake Kit then physically different calipers may be much less important than the larger rotors. In fact he may have reached the same conclusions as Tesla, since the Tesla performance rotor could indeed be Iron with an Aluminum hat. The hat appears to be Aluminum color in Elon's tweet and looks to be a different color than the rotor disc. Sasha also proved his results by coming in second place in a racing series, so his big rotor kit probably works at least adequately on the race track.
6. PM3 appears to have a lower suspension regardless of whether PU is ordered. That would make sense from a build logistics point of view. The likely suspension changes are shorter and stiffer springs, different dampers ("shock absorbers") and possibly stiffer anti-roll bars. These are all very common suspension turning items for sporty sedans like BMW M, Mercedes AMG, Audi S, etc. The lowered suspension may include varied small suspension and sensor linkages, if the Unplugged Performance pages are correct.
Unplugged Performance | Tesla Model 3
7. Braking performance particularly for race track use might be improved if Tesla properly integrated regenerative braking with the brake pedal and friction brakes, as Toyota, VW/Audi/Porsche and many others do. See:
Why Regenerative Braking Belongs... On The Brake Pedal
In particular, Teslas on the race track would both recover more energy and have more durable brakes, if regen were integrated with the brake pedal. That said, note that regenerative braking power is much less than friction brake power, and regen is limited at high state of charge, i.e., when the battery pack is full. (But the pack will deplete rapidly on a race track. Wouldn't be full beyond the first turn.) Friction brakes can sink on the order of a Megawatt of power. Regen, not nearly as much; possibly only 50kW, i.e. 1/20th. Friction brakes are much more powerful than regen, but regen would help on the race track. Even a 5% reduction in friction braking thanks to regen could benefit overall braking and make the friction brakes last a bit longer on a race track.
Racers disable Tesla's default high regen off throttle on the track since it upsets the balance of the car, could make trailing throttle oversteer worse, etc. Regen belongs on the brake pedal.
I doubt new Roadster would be taken seriously as a track car if Tesla does not properly integrate regen with the brake pedal.
The availability of Sasha's big rotor kit takes away most of the risk for me in ordering Performance Model without PU, so I've changed my order back to PM3 without PU. Sasha's kit is 365 mm rotor diameter, and he says it does not fit (is too large for) the 18 inch wheel, so he needs to change out rotors and caliper brackets when changing to the Aero wheels for road trips. Changing those parts is all a bolt on operation and should not be hard for anyone who works on cars.
It's possible the Tesla PM3 rotor is smaller than Sasha's and will fit both the 18 Aero and 20 inch wheels. In fact that seems the only possible answer if they're shipping the same larger rotors with both wheels. Certainly I hope it's the case that the larger rotors are included with PM3 with no PU, but if not, then I can get the larger rotors from Sasha, or possibly the less large rotors from Tesla or whoever supplies Tesla (very possibly Brembo, who have turned into one of the major OEM brake suppliers.)