A fully prepared Street Prepared category Solo2 car is not street legal and would be difficult to drive on the street. Most run extremely lightwieght flywheels and multi-disc 5.5" OD clutches, aftermarket EMS, high spring rates, multi-adjustable shocks, etc. But, you don't have to prepare the car to the limit of the rules.
Go to http://www.scca.org and download the Solo2 rule set under the "Solo" category.
Yup. Rules require NA.
"Typical" SP legal weight reduction is around 15% of the original vehcile weight. I'll be corner weighing the car on Wednesday 7/12.