Stealther

The Stealther, also known as the Sneaky Speeder in Europe and Australia, is a Medium inside drifting bike in Koopa Kart Wii and Koopa Kart 8. It resembles a Yamaha XT660Z Tenere. Its kart counterpart is the Formula Racer. It can be unlocked by earning a one Star Rank or higher for all 100cc Nitro Cups for Grand Prix mode. It is the Koopa Kart counterpart to the Sneakster.

Description
"The Stealther is a really fast bike, but all of its other stats are much lower. You'll need to do well on all 100cc Wii Cups to get this vehicle." - Koopa Kart Wii in-game description