Crash Nitro Kart Hints

You don't have to collect all 4 gems to enter the race in the Hyper Spaceway for the last relic. You only need the blue gem. This is because the warp pad in which you enter the only shows a blue gem x4. But since the gem doesn't change colors, and there is only 1 blue gem in the game, the blue gem will qualify you for the relic race. However, you still can only achieve 100% completion by winning the other 3 gems.