I would go with spending $30-40 on an event first to realize that it will take a lot more than bracing and a suspension to make you quick. My first autox was done in 40 degree weather and my times in DS were about 55 seconds or so. The STX WRXs were doing about 50. Evo/STi (STU and SM) times were about 45. Then one of the instructors took his HS Prius and consistently put down 41 second times.
To paraphrase Lance Armstrong: It's not about the car.