I also haven't participated because of the PF-start.
I didnt have a problem to build one, I had a lot of fun experimenting and building it. But when I continued to build the track and moved the track by using the cut/paste-tool, the driving physics changed. The way the car got through the PF was totally different and the PF-start didn't work anymore. I had this problem not only once, but many times with different PF-attempts.
Why, just why do the car-physics change in relation to the position of the track within the building space?