My guess is more or less like this:
66k
-2.3k (SC access)
-2.3k (autopilot)
-9k (smaller battery, maybe 56 kWh not upgradable after selling)
-1k (smaller tyres)
-3k (less aluminum)
-5k (less margin per unit)
-2k (less gadgets: no LED lights, no retractable door handles,...)
-4k (lesser cost of...