challenges need more options in my opinion

i often feel that challenge options are way too limited, for starters i would like some simple things added like :

1. just like in mario kart ds some boss battles would be nice they dont have to be complex simple ones will do

2.rings   like the one from mario kart wii that have no hit box and that work just like it

3.a counter for getting hit by certain items  example like get hit by  five bananas or collect three mushroom on the floor etc

4.dont go off road (self explanatory)  

5.the abiltiy to have two main objectors instead of one, example collect 50 coins and reach x area ,

6.dont get hit by any item

7. there isn't a place x or higher currently there is just place a certain place but not any thing in between  

8.i know this one is a far stretch but it would be nice to be able to place items in certain areas to complete missions like  for a example bring a banana to the  top of the hill , or place five fake boxes inside a square etc

9. race against bosses just like in  mario kart ds

10. finally just like in mario kart ds some form of star rating like triple stars double  stars etc

i know most of these wont ever come true but hey i can dream lol

I would like the same, although the hoops we say is already included because there is the challenge for x zones, although here you can go in any order

omg and the best one that i forgot was to have balloons in race track courses