My personal favourite (and I've managed a gold in every grand prix) is Funky Kong in the Dragonetti. However it's not so much about the character and kart as how you race. A solid tactic is to remain in around 6-7th place until the third lap, this will mean you get better items - it's not uncommon to come storming through from 7th to 1st with a bullet just before the finish line. If you don't want to use that tactic then you'll need to know every inch of the course and drive a fairly perfect race.
