Tips:
- Hold backwards at the start.
- On dirt, you need to drop speed under 100 for speedslide to increase speed. You can do that by rotating the car slightly and then straightening it back. This works because the game considers a sideways car to always have 0 speed, due to trigonometric equations being used and stuff.
- If you get over 220 (roughly), the Cruise Control will kill your speedslide.
Have fun.