going from a 2003 accord to ANY new car will be a huge upgrade. i'd bet you don't have the following features that many new cars have standard now:
rear camera
bluetooth connection for phone
radar sensors on bumper for proximity alerts
usb ports
advanced power seats
different meters/scales, like mpg, miles remaining, resettable multiple trip meters...
side airbags
fancy collision avoidance in some form
and how's that cassette tape deck working for you? and i'm willing to bet there is a huge fluid spot in your regular parking spot.
now from a new ICE to a new Model 3?????? that alone is great:
no gas tank
regen braking: one pedal driving
OTA updates
autopilot/TACC
huge center screen
safest car out there
instant torque/acceleration, with 5.1 sec 0-60, at worst
comparatively greater cabin and storage space (no hump in the middle of the back seat floor, more head room, no engine)