Battery state-of-health
The single biggest value driver. i4 84 kWh, iX 76 / 105 / 111 kWh, i5 84 kWh, i7 105 kWh packs typically hold up well in chauffeur use. BMW dealer SOH report at point of sale lifts the offer materially. The earlier i3 22 / 33 / 42 kWh packs show more variation; bring a recent capacity reading for the firmest offer.