Career online, or quickplay all count, I just played through the career, then re-done the events to get the perfectionist achievement, after a dozen or so online races I was basically there.

If you are looking this achievement sooner rather than later, don't hit restart as many times as I did!

When trying for perfectionist, I kept restarting if i was near the end of a race and wasn't winning.. simply erasing the fact that I had just drove another few miles