Motorkhanas and the autocross track are very friendly to you car. Khanacrosses can be quite rough as the track chews up. In those instances, it can pay to have a sump guard and a fuel tank guard, and I wouldn't even think about doing a proper rally with out at least a sump guard.
Let me know when your car is log booked and I'll let you know when the next dirt sprint out at hirstglen is. It is a 2 km dirt loop with a corner of every kind possible, quite technical and good for learning your car on, but also very easy to come unstuck on. 2 cars rolled it the last time I was out there. The down side is it chews up tyres.