Every package is categorized as Street, Pro, and Extreme. The latter offers the highest performance increase. Players may also select between various brand packages, which do not have any difference in performance between them.
Street Performance Packages
| Engine/Exhaust Package | ||
|---|---|---|
| Brand Packages | ||
| Cold Air Intake System Cat-Back Exhaust System Replace Headers | Package 1: AEM, Aerospeed, DC Sports, Injen Technology, HKS USA Package 2: NEUSPEED, Jackson Racing, HP Racing, Stillen, Venom Package 3: Skunk2 Racing, Borla, A'PEXi, GReddy Package 4: 5Zigen, Skunk2 Racing, A'PEXi | |
| Increases Acceleration | Unlocked after completing Challenge #6. | Price: 500 |
| Drivetrain Package | ||
| Brand Packages | ||
| Short Throw Shift Kit Shifter Stabilizer Kit Replace Clutch Lightened Flywheel | Package 1: Arospeed, Clutchmasters, Stillen Package 2: NEUSPEED, DC Sports, ACT Package 3: Jackson Racing, HKS USA, Stillen | |
| Increases Top Speed | Unlocked after completing Challenge #6. | Price: 500 |
| Tires Package | ||
| Brand Packages | ||
| Street Performance Tire Package | Package 1: Toyo Tire Package 2: Yokohama Package 3:Kumho Tires | |
| Increases Handling | Unlocked after completing Challenge #6. | Price: 500 |
| ECU & Fuel System Package | ||
| Brand Packages | ||
| Performance Chip | Package 1: Jackson Racing, Venom, Stillen Package 2: AEM, GReddy, Skunk2 Racing Package 3: A'PEXi, Jackson Racing, Stillen | |
| Increases Acceleration and Top Speed | Unlocked after completing Challenge #9. | Price: 1,000 |
| Turbo Package | ||
| Brand Packages | ||
| Stage 1 Turbo Kit | Package 1: HKS USA Package 2: GReddy Package 3: Stillen Package 4: A'PEXi Package 5: Turbonetics | |
| Increases Acceleration | Unlocked after completing Challenge #9. | Price: 1,000 |
| Brakes Package | ||
| Brand Packages | ||
| Street Compound Brake Pads Steel Braided Brake Lines Cross Drilled Rotors | Package 1: AEM, Stillen, Brembo Package 2: KVR Performance, NEUSPEED, Jackson Racing Package 3: Arospeed, HP Racing, Wilwood Engineering | |
| Increases Handling | Unlocked after completing Challenge #38. | Price: 2,000 |
| Weight Reduction Package | ||
| Brand Packages | ||
| Remove Rear Seats Remove Interior Panels Remove Spare Tire | Sparco | |
| Increases Acceleration and Handling | Unlocked after completing Challenge #14. | Price: 750 |
| Suspension Package | ||
| Brand Packages | ||
| Sport Performance Springs and Shocks Strut Tower Bar | Package 1: Arospeed, Eibach, HKS USA, Stillen Package 2: NEUSPEED, Skunk2 Racing, Apex Springs, Bilstein Package 3: H&R Springs, KONI, KYB America, HP Racing, A'PEXi | |
| Increases Handling | Unlocked after completing Challenge #14. | Price: 750 |
| Nitrous Oxide System Package | ||
| Brand Packages | ||
| Dry Shot of Nitrous Oxide | Package 1: Nitrous Express Package 2: NOS | |
| Increases Handling | Unlocked after completing Challenge #14. | Price: 750 |
Pro Performance Packages
| Engine/Exhaust Package | ||
|---|---|---|
| Brand Packages | ||
| Mild Camshaft & Cam Gears High Performance Throttle Body High Flow Intake Manifold Larger Diameter Flowpipe | Package 1: AEM, Jackson Racing, A'PEXi, GReddy, Venom Package 2: Arospeed, NEUSPEED, Skunk2 Racing, Borla, Injen Technology Package 3: DC Sports, HKS USA, HP Racing, Stillen Package 4: Scorpion Exhausts, Henshin Auto, DC Sports | |
| Increases Acceleration | Unlocked after completing Challenge #30. | Price: 1,000 |
| Drivetrain Package | ||
| Brand Packages | ||
| Limited Slip Differential High Performance Clutch | Package 1: ACT, NEUSPEED, Arospeed Package 2: Jackson Racing, Stillen, HKS USA Package 3: HKS USA, NEUSPEED, Jackson Racing | |
| Increases Top Speed | Unlocked after completing Challenge #30. | Price: 1,000 |
| Tires Package | ||
| Brand Packages | ||
| Pro Performance Tire Package | Package 1: Toyo Tire Package 2: Yokohama Package 3:Kumho Tires | |
| Increases Handling | Unlocked after completing Challenge #30. | Price: 1,000 |
| ECU & Fuel System Package | ||
| Brand Packages | ||
| High Flow Fuel Pump Adjustable Fuel Pressure Regulator Replace Fuel Rail Replace Fuel Filter | Package 1: Venom, AEM, GReddy Package 2: Stillen, Jackson Racing, Skunk2 Racing Package 3: A'PEXi, Stillen, Venom | |
| Increases Acceleration and Top Speed | Unlocked after completing Challenge #38. | Price: 2,000 |
| Turbo Package | ||
| Brand Packages | ||
| Stage 2 Turbo Kit w/ Intercooler | Package 1: HKS USA Package 2: GReddy Package 3: Stillen Package 4: A'PEXi Package 5: Turbonetics | |
| Increases Acceleration | Unlocked after completing Challenge #38. | Price: 2,000 |
| Brakes Package | ||
| Brand Packages | ||
| Large Cross Drilled Rotors Race Compound Brake Pads | Package 1: AEM, NEUSPEED, Jackson Racing Package 2: KVR Performance, Stillen, Wilwood Engineering Package 3: Arospeed, Brembo, HP Racing | |
| Increases Handling | Unlocked after completing Challenge #38. | Price: 2,000 |
| Weight Reduction Package | ||
| Brand Packages | ||
| Replace Rear and Side Windows with lightweight polycarbonate Replace Front Seats with Lightweight Racing Seats | Sparco | |
| Increases Acceleration and Handling | Unlocked after completing Challenge #48. | Price: 1,500 |
| Suspension Package | ||
| Brand Packages | ||
| Front and Rear Sway Bar Front and Rear Tie Bar Upgrade Bushings | Package 1: HKS USA, Stillen, Skunk2 Racing, KONI Package 2: Arospeed, NEUSPEED, Apex Springs, HP Racing Package 3: Eibach, Bilstein, H&R Springs, DC Sports, A'PEXi | |
| Increases Handling | Unlocked after completing Challenge #48. | Price: 1,500 |
| Nitrous Oxide System Package | ||
| Brand Packages | ||
| Wet Shot of Nitrous Oxide | Package 1: Nitrous Express Package 2: NOS | |
| Increases Handling | Unlocked after completing Challenge #48. | Price: 1,500 |
Extreme Performance Packages
| Engine/Exhaust Package | ||
|---|---|---|
| Brand Packages | ||
| Replace Piston & Rods Racing Camshaft & Cam Gears Port & Polish Heads Blueprint the Block Low Restriction, High Flow Headers Installed | Package 1: AEM, NEUSPEED, Jackson Racing, Venom, Arospeed Package 2: Greddy, Skunk2 Racing, A'PEXi, Borla, HKS USA Package 3: DC Sports, Injen Technology, HP Racing, Stillen | |
| Increases Acceleration | Unlocked after completing Challenge #66. | Price: 2,000 |
| Drivetrain Package | ||
| Brand Packages | ||
| Six-speed transmission Lightweight & Strengthen Driveshaft | Package 1: DC Sports, ACT, NEUSPEED Package 2: Jackson Racing, Stillen, HKS USA Package 3: NEUSPEED, ACT, DC Sports | |
| Increases Top Speed | Unlocked after completing Challenge #66. | Price: 2,000 |
| Tires Package | ||
| Brand Packages | ||
| Extreme Performance Tire Package | Package 1: Toyo Tire Package 2: Yokohama Package 3:Kumho Tires | |
| Increases Handling | Unlocked after completing Challenge #66. | Price: 2,000 |
| ECU & Fuel System Package | ||
| Brand Packages | ||
| Stand Alone Engine Management Unit Replace Fuel Injectors | Package 1: Jackson Racing, AEM, GReddy Package 2: Stillen, A'PEXi, Venom Package 3: Venom, Skunk2 Racing, Stillen | |
| Increases Acceleration and Top Speed | Unlocked after completing Challenge #80. | Price: 4,000 |
| Turbo Package | ||
| Brand Packages | ||
| Stage 3 Turbo Kit | Package 1: HKS USA Package 2: GReddy Package 3: Stillen Package 4: A'PEXi Package 5: Turbonetics | |
| Increases Acceleration | Unlocked after completing Challenge #80. | Price: 4,000 |
| Brakes Package | ||
| Brand Packages | ||
| Large Cross Drilled and Slotted Rotors Four-piston Racing Calipers | Package 1: AEM, KVR Performance, Arospeed Package 2: NEUSPEED, Stillen, Wilwood Engineering Package 3: Jackson Racing, Stillen, HP Racing | |
| Increases Handling | Unlocked after completing Challenge #80. | Price: 4,000 |
| Weight Reduction Package | ||
| Brand Packages | ||
| Replace Doors and Trunk Lid with Lightweight materials Cut and Foam Fill excess Frame and Interior components | Sparco | |
| Increases Acceleration and Handling | Unlocked after completing Challenge #91. | Price: 3,000 |
| Suspension Package | ||
| Brand Packages | ||
| Coil Over Shock System with adjustable Pillow Mounts | Package 1: Eibach, Stillen, Bilstein, KONI Package 2: HKS USA, NEUSPEED, Skunk2 Racing, DC Sports Package 3: Arospeed, Apex Springs, H&R Springs, A'PEXi, HP Racing | |
| Increases Handling | Unlocked after completing Challenge #91. | Price: 3,000 |
| Nitrous Oxide System Package | ||
| Brand Packages | ||
| Direct Port of Nitrous Oxide | Package 1: Nitrous Express Package 2: NOS | |
| Increases Handling | Unlocked after completing Challenge #91. | Price: 3,000 |
Unique Parts
Unique parts in Underground can be won upon completion of TJ's time trial events. They can not be obtained elsewhere and allow vast improvements on performance.
Overall, three unique parts can be won, with the first one being unlockable after completing event #7.
The player gets the chance to select between an Engine/Exhaust, Drivetrain, and Tire package. All of these upgrades improve handling, except for the Engine/Exhaust package.
Yet another unique part can be won after completing event #27. The player may select a Brakes, Drivetrain, or Tires package for handling. TJ offers a Turbo and ECU package for acceleration improvements.
The final unique part can be unlocked after completing event #96. TJ will offer to the player the following items; Brakes kit, Drivetrain, NOS, Suspension, Turbo, and Weight Reduction packages.
Notes
- By installing an Engine/Exhaust package, the engine sound of a vehicle will be changed.
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