@jessepotter Since you bought a Miata and upgraded its suspension, you seem like someone who cares about the full range of a car's handling. I'll therefore go a bit deeper, beyond what I've ever been able to explore in a normal test drive...
If you ignore the poor stock damping, I think the M3P's
fundamental handling balance and control is actually very good. At least by my standards / based on my experience with sporty cars (my own and friends' cars I've driven, on road and on track). For a 300+ mile range big battery EV (i.e. heavy) it feels wonderfully nimble, playful, fun, and light on its feet. (And it is lighter than any competitive 4 door EV!) Obviously coming from a modded MX-5 it'll still feel like a big tank, but I think it's actually quite good as 4 door family-friendly cars go. Note the stock 20" wheels are ridiculously heavy, switching to lightweight forged 18" wheels make a real difference in how nimble the car feels (beyond what I expected - I mostly did the switch for wheel protection).
The super fast steering ratio + firm smaller diameter steering wheel are sublime for car control, especially on tight twisty roads, or for applying quick counter-steering in a slide. (Fun fact: I once spent $2k on a hand built quick steering rack to change a car from 15:1 to 11.5:1. It was made by a machinist who specialized in rally car parts/builds. I think the Model 3 steering is even quicker from the factory!)
The balance of the car makes it a sweetheart. It's setup to understeer at the limit of course, as any street car should be I think, but it also has a heavy rear bias to the power delivery. So even the dual motor 3 and Y feel very RWD, much moreso than a typical fulltime AWD ICE car (e.g. compared to a manual Subaru or longitudinal Audi). Combine that with perfect sharp EV throttle response and it's super easy to rotate the car with the accelerator, it just does exactly what you want it to. I don't think it has any scary or extreme handling tendencies, or I would've discovered them by now with the fun driving I've gotten to do in this car.
Certainly no signs of snap-oversteer or anything like that!
This is the first car I've owned that can readily power oversteer / drift on pavement, my past sporty cars were all AWD or FWD. But I have pretty solid experience with controlled sliding in the snow and ice (from years past when I had real winters). I got the back of my M3P sliding out real good once under power in the dry, and the quick steering + precise throttle control made catching and recovering from the slide an instinctive breeze. I'm not used to power sliding on pavement at all, not something I could do in my own cars before, yet I felt in control the whole time, like I could make this car dance if I wanted to and had room for it. (Having room to do that safely and responsibly is pretty rare for me, so that one experience is it for now. I can't wait to drive this car in snowy rural mountain roads someday though. Maybe next winter.)
In normal driving mode (outside of Track Mode) the car's front:rear power bias in turns
can feel a bit unpredictable at times, though it's clearly heavily rear-biased by default, you can feel that it wants to rotate under power even before you reach its limits and the nannies clamp down. Which they will if you get up to its limits, and they'll also really limit power coming out of a turn.
That's all fine though because the M3P has Track Mode for those times when you have opportunity to really explore its limits, and once you're in Track Mode the power delivery becomes more predictable thanks to the "Handling Balance" control.
The "Handling Balance" slider adjusts between 100/0 extreme understeer to 0/100 super oversteer-y. It does NOT directly set the front:rear power split, and it does NOT make the car fully RWD or fully FWD, but it does heavily influence the power bias especially in turns, and it feels more consistent & predictable to me than the normal driving mode. I'm told for racetrack lap times everyone finds 50/50 to be fastest, but of course if you're just out having fun on empty roads, set it to whatever you want. I've been using 50/50 for the twisties (for maximum control), 35/65 for empty ramps (some rear bias for easy rotation), and in the snow I'll probably start off around 60/40 or 50/50 initially and tweak it from there. (As mentioned I haven't driven this car in the snow yet.)
Track Mode of course lets you dial back the nannies using the "Stability Assist" slider, and while I'm told it never
fully disables them, it seems to allow plenty of leeway for any driving I'm likely to ever do, including sliding around at lower speeds. (Apparently if you have opportunity to do 70 mph drifts on frozen ice lakes it's still intrusive.
Jealous, I am!) Since it's a slider you can also keep the nannies at pretty much full force if you like, e.g. if you just want to use Track Mode's extra strong regen (see below).
The final Track Mode slider is "Regenerative Braking," and it can actually go
stronger than normal mode regen, which in turn makes the accelerator easier to control because more of the pedal travel gets used for regen. The regen slider is possibly my favorite Track Mode feature. Cranking up regen extra strong feels wonderful in the twisties, you can maintain a much faster pace while still primarily doing one-pedal driving, and of course it's more efficient than hammering on the friction brakes for every turn. The regen is why I love Track Mode for tearing up twisty back roads. (I do dial back the nannies
slightly for the twisties too, just to make sure they don't interfere, but most of the twisty roads I get to have fun on have little-to-no room for error, so I keep below the car's limits and the nannies probably wouldn't be an issue anyways.)
Lastly, I've read that lowering or fully disabling regen is apparently very useful in the snow (so I'm told, no experience yet). Regen in the 3 and Y has a heavy rear bias (for maximum efficiency using the rear permanent magnet motor), so when regen is at normal/full force it's liable to make the back squirrely or even slide. Which is very different from friction brake force distribution of course.
Note that only the M3P and S Plaid get Track Mode, the crossovers including MYP don't get it. I think it's a big part of why Tesla puts a much higher price premium for M3P vs M3LR than MYP vs MYLR. However if you DON'T care for the kinds of driving where Track Mode is helpful, the M3P ends up looking like a poor value! Whereas MYP's minimal price premium is easier to justify over MYLR. (And to be frank, Track Mode and everything else I wrote about in this post is irrelevant to most drivers, and irrelevant to any "normal" driving on public roads with homes, buildings, people, other cars, etc around.)
