I love game 3. It took me about thirty seconds of the first song to get it, but I wasn't positive until the question. As hard as it was to use, the Backlash became my favorite vehicle. I remember when I finally earned the platinum medal on its training stage, I just watched the replay for half an hour lamenting that I had no means of recording it. It was a perfect, absolutely gorgeous run. I eventually gave up on getting all the platinum medals in the game, sadly. There were only four left, I think. At least, there were four levels left that it seemed like platinum medals were available for. Two of them were races that I simply couldn't figure out how to improve on, and two were Pac-man style levels that I couldn't find a pattern for.
The only other one I got was game 5, which I got inside the first measure of the first song. But at least I was able to answer both of those bonus questions, too.