Pedro, welcome to the forums...your manners are appreciated!
The mini-z's go from about 10 MPH (stock) to 18 MPH (modified). Faster speeds are attainable, but you seriously risk major damage and reliability issues.
If ya wonder how tough these cars are...check out this video:
http://www.mini-zracer.com/forums/sh...426#post103426
Cheers, and again, welcome!
If you get one you will be addicted as most of us are now.