ok. do plain simple maths:
every dealership gets approx 15% of catch upon sale of a single unit of vehicle after tax. assuming an XLI is tagged at 2 million a unit. that makes approx 300,000 per unit. selling 5 units a week gets them net value of 1.5 million a week 6 mil a month 72 mil a year. that is documented sales.
avg service bill per vehicle is 7000 after tax. say 25 vehicles a week .documented 15 on cash undocumented.
drop approx 20% sustaining cost .. and you will strike decent digits.