The issue with the current items right now is they hit way too damn hard if we compare this to most kart games, most offensive power ups hit way too hard.

1. UFO, instantly targets the person in 1st needing a specific item to counter.
THIS IS THE MOST balanced item, at worst this item has ever sent me to 1->2nd or 3rd, unless it was a tight pack. Even then I'm easily back in the race. This games BLUE SHELL hits the player the lightest in comparison to most offensive items. I feel this should be the base power of how hard items should hit a player. But right now it's the WEAKEST of them all.

2. Homing Water Balloon or Missile, instantly takes them out, mashing the B or ADADADA makes it go from 2 seconds to 1.5.
This is the most powerful item, yes shields exist but those only become uncommon in 2nd, and common in 1st. The big issue is it's generally powerful enough to take a player from 1st to 8th, and getting hit while in 3rd/4th/5th/6th/7th is just painful. Because if it takes 1st to 8th, getting hit by it just instantly sends you to the back or well behind. You can boost BUT that only gets you back to 100 mph after 1.5-2 seconds of not boosting

3. Water Balloon, easily avoidable but feels way too punishing to get hit by it. Thing takes out you out for 2-3 seconds.
Getting hit by this will instantly put you in the back, but the issue is the people needing to avoid this are hugging the side. But to balance it to be more useful... would mean subjecting people into getting hit by it and instantly want to be take out of the race, even if you're in the lead it can just spawn on you with no warning. While I feel this is one of the items that should hit hard, it feels like it should hit like the current homing items, and lesser based off position.

4. Barricade
Another actually good item 90% of the item, as it will force 1st to swerve and lose speed or get a full to 0 speed drop. My only issue is the number times I've had them spawn on me or in front of me on a turn. Honestly just needs a small touch up on it's spawn placement on turns (mostly seems 90 degree turns are the worst offender of spawning on the person in 1st

5. Storm, Not working as intended
So remember how I said 1st generally will have a double stack of shields, it's pretty much guaranteed that storm wont hit 1st, becoming this reverso blue shell as it will generally make a bigger gap between 1st, or if 2nd has a shield all it does is send 8th to 3rd or 2nd, while 1st and 2nd will have a bigger gap in between them.

Edit:
6. Banana, finally running into these- these feel like the perfect amount of slow down, I've ran into one getting into first place and just slapped me down to 3rd and kept most my acceleration and forward momentum.

Big issue with item mode isn't that it isn't fast imo, but more any item hit wastes you so hard that it puts you 1st to 8th.