*New Update 6/3/07*
I think I'm going to give away the trick to winning this race on the N64 version in the way I did it. First off, you need to know that if you release the acceleration button right before a zipper, you get a greenish boost that is supposed to be faster than the normal purple boost. This is true, however, the game leaves out one small detail. Out of habit, most people instantly slam on the acceleration almost as soon as they hit the zipper. This is wrong, doing so will (in my experience) not give you ANY faster of a boost and may even be slightly less useful. The trick is to keep the acceleration button unpressed UNTIL the green boost dissapears (goes multicolred). Doing so will give you even a bigger boost. Using this tip, winning the race with everyone should be no problem, aside from the characters with horrid turning (Crunch, Banjo, etc).
This is me playing Diddy Kong Racing for the Nintendo 64. I'm racing the first race against Wizpig with Diddy to prove it's not so hard if you use the zippers right, as well as to prove the DS version ruined this race.