Here is the full list of all 16 Colin McRae Rally achievements. It takes around 12-15 hours to unlock all of the achievements on Windows.
Complete the Expert Rally Series in 1st place
Compete in at least 1 rally in Australia, Greece and Corsica
Complete the Mixed Rally Series C in 1st place
Start a stage in the Lancia Stratos
Complete the Greece Rally Series in any finishing position
Complete the Corsica Rally Series in any finishing position
Complete Mixed Rally Series B in any finishing position
Complete the Mixed Rally Series A in 1st place
Start a stage in the Mitsubishi Lancer
Finish a stage with all four areas damaged to the maximum possible amount
Start a stage in the Subaru Impreza
Complete the Australia Rally Series in 1st place
Complete the Introduction Championship in any finishing postion
Complete a rally in 1st place for the first time
Complete your first stage
Start a stage in the Ford Focus