Not sure it's fair to call a $120K - $140K† kit (not including the cost of having the engine and avionics professionally installed) "homemade", but still an impressive flying achievement for the 17 year old pilots.
We are, and there's nothing wrong with that.
Getting that distance in a little plane would be impressive. Somebody even went around the world, so it can be done. One ends up flying a wing-shaped carbon-fiber fuel tank.