Grand Prix mode 100% complete! I wrapped up getting three stars on every cup with the Mirror Mode Special Cup not long ago, and of course it had to end with a close call on Rainbow Road. (No, not this one.) It took me countless attempts, but I finally managed it!
And do you want to know what the most insulting part is? Afterwards I unlocked the Cyber Slick tires, which are said to be among the best for pure speed builds. That's right, I went all this time without unlocking Slick or Cyber Slick tires, which are quite literally the only variant of vehicle or part you don't start out with. (Along with Metal Mario and Pink Gold Peach if you count characters.) So I decided to use them to unlock the heavyweights' stamps (since at that point I'd only obtained the super heavyweights', along with the Mii's), and one of the cups I did was Mirror Mode Special Cup. And I absolutely destroyed the competition in every race! Including Rainbow Road!
I'll put that down to me driving really well in that one race, along with no blue shell mishaps or anything of the sort, though, because after doing some tests I still think I like the super heavyweight with Roller tires build better.