This is where you can download the OSX and Windows Demo of StuntMANIA!jnr.

Are there any limitations in the demo version?
Yes.
You are limited to playing only one stunt car (Razor).
You are limited to playing in one environment (Trixter Park) but in both Daytme and Nighttime modes.
You cant play AIR SPEED FREAK or BONUS ROUNDUP Games.
You dont have the new GRAVITY Powerup
You can't save your scores.