I will try my best at creating a 'map' of any track and I have completed ALL World Tour races,but I can't HELP you with the races,what you unlock only.

I will help with races. In SP Races, you should accumulate nitro lvl3 (boost the overload) than use one unit to overtake the SP car than when he gets close (except Hijack and Wild Gang) BOOST!!! (usually). In Ex Races the first races in each tour is easy, but for the last one, keep boosting until you get to the leader. Go easy, since if you overtake the leader, he'll overtake you no matter what. (I got hit by the leader in Rave Racer 2 in the last race and I went about 620 kmh)

...bored, Back to work for me