When your tires are worn out do a burnout in your highest gear. When the RPMs are in the red downshift to 1st gear keeping the brake on the whole time. If you have done this correctly you will have 4 Wheel Drive.

The following cars are unlocked when you win the corresponding event.

Unlock Pagani Zonda C12:
Win the Professional (High-Power Open).

Unlock Porsche #26 Porsche AG 911 GT1-98:
Win the Endurance (Porsche 911 GT2 Cup).

Unlock Toyota Celica 1800 VVT-i:
Win the Amateur Front-Engine RWD Event.

Unlock Toyota VIS Racing MR2 turbo T-bar:
Win the Point-to-Point Mid-Engine Event.

Unlock Porsche 911 GT2:
Win the Point-to-Point (Club 911 Event).

Unlock Renault Sport Clio V6 RS:
Win the Amateur (Hatchback Challenge).

Unlock Porsche 911 Carrera RS:
Win the Professional (Class B Championship).

Unlock Toyota APR Performance Celica GTS:
Win the Point-to-Point (All-Wheel-Drive Event).

Unlock Porsche #17 Racing Porsche AG 962c:
Win the Endurance (Class R-P1 Championship).

Unlock Porsche #23 Alex Job Racing 911 GT3-RSR:
Win the Championship Series (Class B Championship).

Unlock Shelby Cobra 427 S/C:
Win the Championship Series (Classic Sports Car Event).

Unlock Toyota #27 GT-ONE TS020:
Win the Championship Series (Class R-GTS Championship).

Unlock Toyota Border MR2 Turbo T-bar:
Win the Point-to-Point (Front-Wheel-Drive Event).

Unlock Acura #42 RealTime Racing NSX:
Win the Championship Series (Club NSX Event).

Unlock Subaru Impreza WRX STi Spec-C (J):
Win the Point-to-Point (Rallisport Face Off).

Unlock Toyota 2000GT:
Win the Professional (Class D Championship).

Unlock TVR Tuscan R:
Win the Professional (TVR Tuscan Cup).

Unlock Volvo #25 At-Speed S60 R:
Win the Endurance Class D Championship.

Unlock Shelby Series 1:
Win the Professional (Shelby Cobra Cup).

Unlock Subaru Impreza 22B STi:
Win the Amateur (Rallisport Face Off).

Unlock Toyota AE86 Sprinter Trueno:
Win the Amateur (European Open).