It's just as fast as any other Ofna buggy that comes stock with the Force 26 =)
It's a decent stock motor and I'm sure you'll be happy with it's performance.
Buggies aren't generally designed with ridiculous amounts of speed in mind. Even if it were a 2 speed, on most tracks there's simply not enough runway to make use of it, and it'll just get in the way. They are designed with lots and lots of torque and low end power in mind, so you can quickly get up to speed after a corner, up a ramp, etc. Off road man! Yea!