Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Collector (100 points): Unlock every vehicle.
Strong Finish (100 points): Complete the career.
Perfectionist (100 points): Place 1st in every career race.
Weekend Driver (25 points): Drive a total of 250 miles in career, exhibition, System Link, and Xbox Live.
Marathon Wheelman (50 points): Drive a total of 500 miles in career, exhibition, System Link, and Xbox Live.
Baja Ironman (100 points): Drive a total of 1000 miles in career, exhibition, System Link, and Xbox Live.
Unlock 2nd Ticket (10 points): Unlock the 2nd ticket in the career.
Unlock 3rd Ticket (15 points): Unlock the 3rd ticket in the career.
Unlock 4th Ticket (20 points): Unlock the 4th ticket in the career.
Unlock 5th Ticket (25 points): Unlock the 5th ticket in the career.
Unlock 6th Ticket (30 points): Unlock the 6th ticket in the career.
Unlock 7th Ticket (35 points): Unlock the 7th ticket in the career.
Unlock 8th Ticket (40 points): Unlock the 8th ticket in the career.
1st in Endurance #1 (40 points): Place 1st in Endurance Regional #1.
1st in Endurance #2 (50 points): Place 1st in Endurance Regional #2.
1st in Endurance #3 (60 points): Place 1st in Endurance Regional #3.
1st in Endurance #4 (70 points): Place 1st in Endurance Regional #4.
Feet Wet (5 points): Finish any race in career, exhibition, System Link, or Xbox Live.
Dead Man's Curve (5 points): Wreck your vehicle in career, exhibition, System Link, or Xbox Live.
Podium (10 points): Finish any race in first place in career, exhibition, System Link, or Xbox Live.
All Skill (25 points): Finish any race in the top 3 without any damage in career.
Pink Slip (5 points): Win a head to head race.

Additionally, there are four secret achievements, all of which are currently unknown:

Secret achievement (20 points): Unknown.
Secret achievement (20 points): Unknown.
Secret achievement (20 points): Unknown.
Secret achievement (20 points): Unknown.