Powerful Boosts In Crash Zones:

This trick works in one player and two player modes. When you are doing the crash zones, at the start immediately hold R for a boost. After a few seconds, press it again. This should give you more boost, which results in a faster speed and better crashes. Repeat this as many times as desired. Additionally, when you are doing Crash Zone 7 "Whip Up A Storm Of Metal And Glass", go to the right onto the dirt. You can have a wider angle to turn left at the intersection, and therefore have more speed for a greater crash.