First, some changes I would make as soon as penguinly possible:
- Navigation MUST offer a choice between north-up and track-up orientation.
- Volume needs MUCH finer granularity. 11 steps are nowhere near enough... 30 or more, please.
- Offer the option to buy more storage for music, or to plug in an extra SSD for more music
- Rear-seat power (AC or DC) so the kids can play or do whatever...
- A third and more aggressive regen setting (call it "sport")
- Choice of codecs and bitrates for stored music (so I can use much higher-quality settings)
- Remote control/notification of some things via an app. For example, let me start the A/C while I'm still in the mall so the car cools down.
- As many things as possible should be configured into the driver's profile, so the use of your key fob makes it "yours" as much as possible
- Ability to send an address or route to my car over the Internet, or to edit its contacts/addressbook remotely
- Ability to access my car's music storage over the network, so I can upload music or video, or ability to "sync" car with computer
- Voice commands to the car (see below, too)
Then, some other things that'll take a little more time...
- Downloadable logs like the Roadster, so I can track a ton of things about my car's life and performance
- Adaptive cruise control, capable of bringing the car to a full stop in the shortest distance physically possible.
- Dual-motor all-wheel-drive for maximum performance
- 300-mile real-world range (85 mph, A/C maxed, with some passing and acceleration involved)
- The ability to fit significantly wider tires (say, up to 285/30) for disgusting amounts of grip
- Ability to put transponders in the nosecone
- More in-car storage options (doors with fold-out pockets, like the 2009 BMW 3-series, and options for opportunity console)
- Xenon or HID (best technology available) headlights that turn to follow a curve
- Powered folding mirrors
- Heated steering wheel
- Heated and COOLED front seats
- Voice commands to the car which are able to recognize and ignore the music being played
That's all I've got for today...