You can change brakes, suspension, lights, pretty much everything without software locks. Only drive train is locked, which rarely fails and it does so progressively.

Also you can enter service mode now and tell it to reflash the whole car. Need a new steering rack or camera for example? Swap the part, hit reflash and the car flashes the correct vin, coding and software into the part and offers calibration afterwards.
Also built in scantool to read fault codes and do basic diag. More advanced diag needs Tesla Toolbox. Costs $165 for a day of access/$500 per month, but is possible with an ethernet cable and doesn't need a $1800 SAE J2534 box.