They had a sprint car class at the oval track i race at this weekend and i have to get one

They look like they are a blast to drive and very fast once setup right.
What are the best options? One of the cars was a Custom Works car, and the rest were buggy conversions. They were all running pretty close to each other, but the guy with the Custom Works sprint had just got it, so maybe it would shine once setup correctly.
What are the pros/cons of each.
Im wanting to race it on carpet oval on friday nights and dirt oval on saturday night. The dirt oval is extremely smooth and is comparable size to the carpet oval.