Model 3 onboard charger info:

I just picked up my new Model 3 in San Diego county. I love it!
As others have said the options for delivery now (April 2018) are limited to:
Base price $35,000 but you must also purchase:
Long range battery (310 mile range) +$9,000 (also adds ~275 lbs to the curb weight)
Upgraded interior (it's very nice) +$5,000 (lot's of nice extras like upgraded audio sys)
delivery charge Approx +$1,000 (San Diego, CA)
plus sales tax Approx +$4,500 (CA 9%)
I also purchased:
White pearl paint +$1,000 (beautiful)
19" wheels +$1,500 (really cool) (note that the Aero wheels add ~5% more range)
auto steer +$5,000 (pay attention on curves)

The included on board AC charger has a Max charge rate of 48 amps like the late model s.
The included mobile charge cable can be plugged into a 240VAC 14-50 socket but the cable itself is limited to 32 amps max (20mi/hr charge rate) (40 amp breakerX.80= 32 amps)
To take advantage of the higher 48 amp on board charge rate you will need to purchase the home wall mounted charger. ($500) from Tesla.

You will then need a supply circuit with a 60 amp breaker (60 amp X .80 = 48 amps max by code).
Don't waste money on a larger breaker because while the home charger can provide up to 80 amps to a model s with dual chargers the model 3 is limited to 48 amps max. (30 mi/hr charge rate). This is the fastest way to charge a model 3 at home. (really fast)!
Note that Tesla Superchargers charge a lot faster because they are DC to DC and bypass the onboard AC charger.
FYI: the onboard AC charger converts your home AC to DC internally to charge the DC battery.
Cautionary note: Don't make a habit of charging you battery totally full. This will reduce battery life and limit the ability to do regenerative braking. Tesla recommends that you use 90% as the charge limit. (310 mi range X .90= 279 miles)
Hope this helps............ Bill