Specials
Special in other Kart Games
Diddy Kong Racing had specials that wheren't stored in boxes and then randomly assigned after collecting them, but instead used different colored ballons. A red one would be turbo, a green one would be oil, blue one would be a magnet another one a rocket, etc. While the overall number of items was small, Diddy Kong Racing allow to 'chain' them, collect two turbos in a row and you get a more powerfull one, collect one rocket and you get an unaimed one, collect another one and you have a homing one. This worked with all items up to three levels. Chaining only worked with all the same item type, so if you collect a turbo and then a rocket you lose the turbo and only get a level1 rocket.
Crash Team Racing has specials that come in two forms depending on how much 'Wampa Fruit' (Coins/Herring) you've eaten.
Another possibility is to allow you to collect two different specials and have them combine to make a new kind of weapon. So if you have an oil slick and a missile, you get a missile that creates an oil slick wherever it lands. If you have a 'turbo' and an oil slick then you get a stripey oil slick that not only makes you lose steering control - but also slams you forward very fast (making it more likely you'll hit a wall). Not all of the combinations have to be beneficial...collecting a parachute and a missile might make a missile that can't go anywhere and explodes in your face.
This combination effect could make for some interesting tactics in 'battle mode'.
In both Crash Team Racing and MarioKart'64, you collect specials from anonymous boxes - you can't tell what you're going to get until you've gotten it. However, when you collect the item, it cycles through a number of different collectible items before settling down on the one you'll finally get - hitting the 'use' button before it stops by itself gives you a chance to choose which item you'll get - although it takes good reactions to get the right one. Think: one armed bandit reel. Weapons as Shield
Mario Kart'64 allowed to use weapons as shield, thus giving them two different functionalites at the same time. If you collected three shells (they come packaged into a single item) they float, once activated, around the player and act as a protection against other items. Problem is that they are way more powerful than many other items. Another way to use a weapon as shield, which already was present in the Super MarioKart on SNES, is to hold a item behind the kart by holding the special-button pressed, thus if a shell was going to hit the kart, it got blocked of by the item. As opposed to the three shells, this way was much more balanced.