ViolaBouquet

I'm a bit annoyed with the costume idea. I would love for to costume to stay on the whole level and have a few different versions (fire and big).

Here are a couple levels of mine if anyone is interested. I try to go for a quality level and only have one just random silly tricky one called "run and jump". I'll start easy and work to more difficult on these four.
Spooky Forest (1CDD-0000-00E5-3B3B)
Bowser Manor 2.0 (F979-0000-00D8-BD1C)
Gravity Shift (0FEF-0000-00D8-A93E)
The Dark World (CFEF-0000-00D8-A42D)

@-DG Awesome. I'll have to check yours out. I had a few more "gimmick-y" levels, but are slowly taking them doing. I first thought it was fun, but now I feel like I can do better.

Since people are posting theres, I have a few. I strive for a good experience in the level and have deleted more than are uploaded.
Bowser Manor (B502-0000-00CD-6FB2)
Goomba Cove (2920-0000-00CB-3ACD)
Journey Through The Inferno (5885-0000-00D1-10BE)
To The End And Back (A7B7-0000-00D1-2D74)
Break Free! (FDFD-0000-00C3-6A18)

Let me know your thoughts on where I could improve. Thank you.

@geoluigi A difficult level doesn't mean a good level.

Heaver kart doesn't matter. Acceleration I would say is best since it will get you going again after hits or running into walls. The biggest thing is to take as close to the wall and corners as possible. In Toad's Turnpike you're driving after the middle of the road. Drift right next to the wall (Although takes some practice) will get much faster times throughout.

I hope they throw in Birdo in one of those packs

There better be a Birdo DLC... or else.... I'll still play the game.