Items to Check Before Accepting Delivery
Ask your insurance company for the Hybrid or Electric Vehicle discount.
Call the dealer the day before delivery to have them start charging it. Believe it or not, some do not yet have Level 2 EVSEs installed and can only charge from a 120 volt outlet.
Your car is delivered with both charge rates purposely set to low. You need to go into the idrive settings > Charging and adjust to maximum setting. Be aware that you can set these yourself and you might need lower settings depending on available current when charging. Please be aware that some new cars have experienced a KLE failure and BMW is working on a solution. It may be better for the the short term to keep you charge rate set to low until all i3's have been exposed to the new solution provided by BMWNA.
Check to make sure the AC and charging system is working before you leave the dealer; BMW disables both for shipping and the port or dealer needs to enable it before delivery. There were quite a few people in Europe that had this issue. It is evidently a 15 minute fix to enable the A/C at the dealer, provided your dealer has been trained on this and knows how to do it! NOTE: if it is blowing well, but not cold, make the dealer check for missing fuses - missing fuses has been documented as a source of AC troubles.
Before you leave the dealership, put the car into reverse with no surrounding obstacles and verify that the sensors all work.
If you are getting an an Electronaut Edition i3 Rex without the Technology Package, you may be missing the default code 606 navigation package. Make sure it is there before you take delivery.
Check to make sure the tow bolt is located in the frunk of the car or elsewhere. Page 195 of the owners manual says the tow fitting is located in the storage compartment under the hood. It should be wedged into the foam caddy for the tire inflation kit.
Ask to see the battery log and review it to make sure that the car has been checked and not allowed to go dead - if it looks suspect, ask to have the 12V battery tested rather than merely charged. There have been numerous failures of the 12V system and a leading hypothesis is that the 12V batteries in these cars was allowed to fully discharge and become damaged in transit.
Just keep an eye on the battery coolant level for few days- ask the dealer to show you. If cars had air trapped in the system the level looked correct at delivery but with use it gets too low and why wait for the sensor to alert you much later and scare you? For such an easy check, why not do it pro actively. Visually check the brake fluid while you are at it (later on, that tells you the wear off the pads too, just like on any car- assuming no brake leaks) (From Bogdan Alex).
Make sure tire pressures are set correctly. Sticker says 33 psi front and 41 psi at the back. (Mentioned by Vance Bodell).