This thread suggests that nominal impedence for the LX factory system speakers is indeed 2 ohms.
https://forum.ih8mud.com/100-series-cruisers/372571-mark-levinson-speakers.html
But for practical purposes, it doesn't really matter. If you replace the crappy factory speakers with good quality aftermarket speakers, your system will sound better.
In theory, if you use speakers with nominal impedence ratings much lower than the factory speakers, and turn the volume up very loud, you could fry the amp. But in practice, it would be difficult to find aftermarket 6.5 " car speakers rated at << 2 ohms.
Any speakers with nominal impedence of ~2 to 4 ohms will work fine.
What I am saying is that it is not important to exactly match the impedence rating of the aftermarket speakers to that of the factory speakers.
If you were to replace only one of the factory speakers with aftermarket, then the aftermarket speaker might be louder or quieter relative to the factory speakers, due to differences in impedence, efficiency, frequency response, and other factors. This could adversely affect your ability to adjust the balance and fader. But if you replace all four of the factory door speakers at the same time, then go with whatever drivers will fit in the holes and are within your budget. Don't worry too much about matching the impedence characteristics of the factory system.
Measurements of speaker impedence taken with a multimeter from radioshack will not really give you any useful information because the impedence of the speaker depends on the frequency of the audio signal, impedence of the speaker wires, temperature, and other factors. The 'nominal impedence' ratings on car speakers can be useful when designing a complicated multi-driver system, but if you just want to replace your factory 6.5s with something better, don't get too hung up on the impedence rating.
Hope this helps.
