Loudspeaker Cabinet Simulators are only as good as the TS Parameters you enter in the software.
Literally measuring the TS Parameters of the driver to ensure the figures reflect the manufacturers specifications is the best option. Fortunately, there are programs such as ARTA, CLIO in addition to the Woofer Tester that can make such calculations.
The next step would be to literally measure the loudspeaker’s performance in terms of frequency response in addition to the impedance curve in the box under real-world conditions. Once you have created an enclosure around a particular loudspeaker, there is a greater chance of achieving the requirements you are aiming for.
Unfortunately, many are not willing to go through the trouble of learning free loudspeaker design software more so getting acquainted with measuring TS Parameters of a loudspeaker. They rather find a design on the Internet, build the box, place speakers with TS Parameters that differ from the recommended driver assigned for that particular box, and hope for the best.
Possibly, I am a tad too old fashioned. For the only way I know to determine the thermal or mechanical limit of a loudspeaker is to literally drive the speaker until you smell something is burning, see smoke or hear the voice coil crashing against the back plate.
Best Regards,