Just a small visual addition I thought of that would compliment the game more:
When you drive over vegetation like small plants or grass, it would look nice to have it flatten down. Playing the arena and driving over all the purple grass and leaving a trail through it would just be so satisfying.
Not sure I would handle trees or larger kind of vegetation, though. I definitely think hitting a tree or big alien plant should effect your forward momentum.
Or you could do it how rollcage did it and just make it explode, but michael bay style.