I think if you want a Mario Kart sort of approach, the Projectile is somewhat always linked to the ground. So I’m not too sure how the physics would work that way.
I’d almost be tempted to say to not use projectile component and instead treat that projectile like a character with an AI component as it needs to stay on track, hop off bumps and still hover the ground mostly. With a good movement component set up, no friction and an AI controller it should be doable.
As for the collision, a sphere is more efficient than a complex static mesh collision (and just as much fun).