Yes, neither are Mario Kart games. But they are spiritual siblings to the Mario Kart games and should be drafted into the Mario Kart series. Both have some great courses that would be at home in Mario Kart. Diddy Kong appears in the Mario Kart games anyway (not sure about MK8) so he is the link to Diddy Kong Racing. And in the absence of a Stunt Race FX series appearing, it may as well be aborbed into Mario Kart.
Besides, both would add some much needed freshness to the somewhat stale concept of the retro courses.
Edgey, Gumshoe, Godot, Sissel, Larry, then Mia, Franziska, Maggie, Kay and Lynne.
I'm throwing my money at the screen but nothing happens!