Here's some random tips:
*The fastest combo is funky kong with the flame runner bike, if anyone needed help. Of course, that doesn't really help if you're trying to unlock funky kong (like me lol).
*A good way to get a fast time in grumble volcano is to do what the regional/ world champions (on rankings)do (watching their replays helps to figure out how to do it) which is climbing up the rock to the left of the starting line. it's pretty hard to do but its helpful.
*in luigi circuit, at the end where all the boosts are, you can cut across the grass with a speed boost for a shortcut.
~EmmaatMK
*