What is the ground clearance of a matrix TR ARENA? Where I would drive in has rocks in some places.

The ground clearance is going to depend on how you set it up. The rear can be as high as 4" and when the arms are level 1 3/4". The front can be as high as 2 3/4" and with the arms level 1 3/4". So you decide and adjust using the spacers included.

You wont regret the Arena, I love mine!!!