I noticed I had an unusually fast Wario run during my All Presents WR attempt. I thought it might be my brain believing it was fast after not having any sleep for 26 total hours at that point, but upon reviewing it I realized I not only got a new world record in the hard mode category, but I got the fastest story mode ever completed for Mario Party 4.

The timer starts this story mode at or around 22:02:38 and ends at or around 26:29:21, making the run time about 4:26:44, an 8~ minute improvement on the old Hard Mode world record. This is the video with the timer starting at 0 and ending at "Finish" after defeating Bowser: