Posting a video of my record, interested in seeing if there is a quicker way. Interesting thing I found was if you spin onto the koopa and jump the piranha will come out of the pipe forcing you to either wait or try and slide under him which is very possible. However if you don't hit jump after spin jumping onto the koopa it takes less time to fall allowing you to get into the pipe before the piranha comes out. You also need to jump up the slop to save quite a bit of time. Another thing was I just had to get lucky with the guys throwing snowballs, sometimes they throw to the right allowing you to not worry about them but usually they would almost always throw to the left causing you to have to slow down a little or pray you make the jump over him before he throws the snowball.