I'm not an engineer (at least not the right kind), but HW3 is a finished product in mass production. There won't be any tweaking or changes.
Doesn't work the same way as with an entire car.
That's not correct at all... manufacturers constantly revise parts.
See below.
Good point!
If it's a hardware improvement, wouldn't we be expecting a version number higher than 3 such as 3.5 or 4.0?
Nope.
You'd expect same PN, higher rev letter.
For example let's consider the infamous 980 rear drive unit in the Model 3.
Part number is 1120980-00-G
Older versions of that same part were 1120980-00-F, 1120980-00-E, and so on....
Same basic part, but small tweaks along the way.
Could be as simple as a slight improvement to a connector so it's sturdier...or maybe they found they need to make slight improvements to prevent some specific internal failure of the part, so a billion other little things not worth a whole new part number.
In this cases the newer revision is usually better (or sometimes equivalent but easier/cheaper for the MFG in some way)- and typically if a part goes bad they'll swap in the whatever the newest revision of that same part is (since in theory it's as good or likely better)
None of this necessarily means there's gonna be a PERFORMANCE difference.... but might be tiny reliability differences.
Which, as long as they keep not providing any real functional advantage to HW3, means waiting a bit longer isn't a bad plan.
Doubly so because it also gives SCs more experience doing the installs in the meantime.
I've read that HW3 can now see cones, trash cans on instrument clusters while those versions below HW3 don't.
So, there's definitely a difference.
It can display those, yes. Actually
do anything differently concerning them? Not so much.
2.5 sees cones too (there's video of it reacting to them even) it just doesn't show them on the screen.