Double Dash!! is the best-designed Mario Kart. There's not a single bad track and mechanics all exist in perfect harmony, most notably the Item roster and the effects of said items. The only flaw may be the unbalanced Vehicle roster where one vehicle is clearly the best (Barrel Train), with a few others also being pretty usable (Toad Kart, Pirhana Pipes, Parade Kart). The special items are also fairly balanced surprisingly, Peach & Daisy have pretty fucking dogshit ones and Mario & Luigi are nothing to write home about but the others you could all make a case for choosing. Koopa/Paratroopa have very common triple shells, DK/Diddy has the Giant Banana very useful for frontrunning, Bowser/Jr has the Giant Shell which is very funny, Toad/Toadette has the Golden Shroom you can get in FUCKING SECOND PLACE, Yoshi/Birdo has better Red Shells that sometimes have stars in them, and Wario/Waluigi have bombs which are kinda hard to use but the fact that they shoot people up into the fucking air and completely kill their speed still makes them pretty good. Petey/Boo are purposely OP and have all items but it's kinda made up for by the fact that heavies suck since they can't use the Barrel Train. And also they're rewards for basically 100% anyway.