Researching the available options is. Will i my stock jetta be competing against a fully build m3.

Why You Should Run Autocross Even If Your Car Is A Hunk Of Crap
How to build an autocross car. Once a driver gets a taste of autocross he immediately starts making a checklist of modifications to go faster. Autocross is about attacking the course extremely hard and doing so straight off the bat. Because scca solo uses rubber traffic cones to build a course in large parking lots or on inactive airstrips the hazards and barriers to entry are low and that makes autocross one of the easiest and least expensive ways to compete in a car. Autocross is a relatively safe and legal way to compete with your own car. The rx 7 is a competent cone carver as well thanks to its lightweight rotary engine and expertly balanced chassis. Here is what i do to make my car safe and competitive for autocross and track events.
In autocross it is understood that the varying types of cars make for an uneven playing field. At the entry level it is useful to have a basic knowledge of vehicle handling and dynamics. Most cars dont even require any preparation but doing these few simpl. Where possible do your homework before purchasing components. Autocross driving skills such as acceleration braking shifting weight transfer slalom and driving lines are explained. The miata isnt the only great autocross car mazda has built.
You dont get a chance to build up to speed so you must explode out of the blocks like usain bolt. Well let me tell you. This one is for. A very reputable and well known autocross driver danny popp offers this advice to anyone new to the sport your car or truck needs to be reliable not fast. This book includes basic modifications for tires and suspension and more advanced modifications for mid to top level classes. Use facts and data to compare your chosen models against each other to make a more informed decision.
You know that all the cars on your list are proven winners so what more do you need to know. Teaches car setup driving skills and modifications for autocross racing. Build your own entry level autocrosssolo car knowledge level. This is where you can really fine tune your search for an autocross car.