I use luigi or Diddy Kong in the blooper kart. I haven't played the game in forever though.. so I forgot the name. =\ Sadly, none of my friends like playing MKWii..

That Blooper themed kart is a little too good, though. I tried it today in one of those weekly tournaments and the handling made driving through those rings a chore. I think I'm going to go with Rosalina on the Mach bike. She handled herself pretty well online earlier.

For races with many people (9 and above) I favour Baby Luigi on Bullet Bike. For races with fewer people I favour Daisy on Mach Bike.

I wonder how the hell people are able to use Daisy, her voice is seriously horrible. The hell were they thinking...

I stick with Peach on Mach Bike, mainly because I hate the baby characters, and I hate Daisy. It's nice being heavier, too. If I were to pick a light, I'd go Toadette (guess I go on looks/voice).

I use Peach for everything, though I think I'll go heavy for smaller races in the future. Just too lazy to change characters. I don't like Funky Kong either, hopefully Rosalina isn't as annoying (haven't tried her in a while).

If you're playing competetively then use Funky Kong on the Flame Runner. Most time trial world records have been done with that setup.

Funky Kong and Bowser Bike. But not for the ice and water levels, I forgot the name of those bikes but they are good on off-road terrain. I haven't played the game for a long time so I can't remember.

Mario + Dolphin Dasher for races
Bowser + Bowser Bike for Time Trial

Luigi in the Mach bike

I usually like to use Toad or another "light" player and the Cheep Charger. That thing is FAST.. just make sure you stay away from all the other drivers when you use it because it gets knocked around a lot.

Peach and the Mach Bike. This makes me a loser as Rol says.