[Donny]

back in the 90's when i worked for a holdon dealership all our staff could buy their new fullsize local cars for around 5k staff discount straight off rrp.
the principal was a pretty tight and shrewd operator, and i would guess he had another 2k or so profit margin in the base dunny doors, perhaps more as the models went up in fixture levels etc.

there isnt a lot in them margins wise from what i saw of my time at the dealership.

the biggest profits came from the service department that had 100 plus cars a day in and out of it every weekday (before workshops opened for weekends and nites).
spare parts allways does well, they sell to the retail public, to the trades as well, and also charge the service dept for all bits used in services, repairs etc, and the service dept bills the end customer full retail.
oh and dont forget the warranty dept was also a good avenue for money back too.

then add the used car lot, where a wily manager will wrangle every dollar out of a sale/trade, and the markups and GP amounts can be pretty impressive here too.

i noticed all that in the few years I worked at the dealerships.

And as someone said above, they make a killing on accessories like tow packs, mud flaps, louvers, shades, tinting etc etc, then add and warranties and finance.
Thats why they allways have a decent lookin chicks to sell all this stuff, suckers some men in nicely.