Common misconception. Typically the fastest line will include keeping as much speed in a straight line, hard braking, then being able to point the car down the next portion of the track with as much speed as you can get by your track out point. I know this doesn't make sense without a pic, but I don't have one! Use your imaginations!

Driver does make a huge difference. That's why I recently passed a Ford GT in my '96 Firehawk (still stock) at Gratten. Unfortunately, (or fortunately for me) he wasn't pushing it hard so it was kinda funny to see. I have lots of examples like this (I can't believe I've been doing that for over 10 years now...), but let's just leave that as the prime example of a more capable car being passed by a less capable one.

Anyway, I agree with the both comment. They seem complimentary to me. The reason I got into single track mountain biking is a lot of set up for the corners follows similar set up in autos. I use both to train for the other. Both will leave you sore the next day too. I can only imagine that a critrium is similar but I don't have this experience.