Actually, that is quite far from the truth. over 80% of Sierra-2EXv2 out there are from purchasing the complete speaker, not upgrades.
LX is the more popular speaker with regards to sales volume, but after checking it is only about 10% higher. Overall customer satisfaction rate is essentially the same between them, both have very, very low return rates.
It will be interesting to see the numbers on the Sierra-1 V2, once we have compiled enough data.