NOTE: These are the main Need for Speed: Underground cheats that are usually applied by pressing down the right key combination. Please find the instructions on how to use these cheats below.
Unlock all circuit tracks
At the main menu, press Down, R, R, R, X, X, X, Z.
Unlock all drag tracks
At the main menu, press Right, Z, Left, R, Z, L, Y, X.
Unlock all drift tracks
At the main menu, press Left, left, Left, left, Right, X, R, Y.
Unlock all sprint tracks
At the main menu, press Up, X, X, X, R, Down, Down, Down.
Drift physics
At the main menu, press R, Up, Up, Up, Down, Down, Down,
L.
1988 Nissan Skyline GTR34
Select underground mode and complete at least the first
80 missions. A recommended car to use is the Acura RSX.
You will then challenge Samantha. Defeat her under the
medium difficulty setting and win the next drag race to
unlock the 1998 Nissan Skyline GTR34.
Eddie's: Nissan Skyline
To unlock Eddie's car in the end, keep winning style points.
Note: It is faster to win them in drift. When your style
meter maxes out, a message stating that you have won Eddie's
Nissan Skyline will appear.
Samantha's car
Keep getting style points until you get all the vinyls,
then fill up the next meter.
Kurt's Killa Ride
Use a Stock Mazda RX-7 and keep trying until you win.
Easy drift points
Simply stay behind a car and watch the points rack up.
Turn off the stability control by going into options and
selecting "Car". This will make the car drift
easier.
Easy wins
If you are having trouble winning circuit, sprint, or
lap knockout races, take off all of your engine performance
mods. Note: This works for every car, is most useful for
the Nissan Skyline. You do not need to take off the handling
mods.
Easier drag wins
To get to higher gears quicker in drag races, tap L repeatedly
as needed to increase the RPM to the appropriate level
to switch the gear. This also lessens the full force of
the nitrous to lower the chance of burning the engine
out.
Easy style points
After you unlock the oval drift track, go into "Quick
Race" and choose that track. Then, race around it
using the handbrake to powerslide into the corners. Depending
on how good you are, you will unlock rewards every time
you fill your meter, which does not take too long.