Most of the IT cars run NASA Performance Touring (PT). Some IT cars may run a spec series but there is no Spec Saturn. There is no direct ITA to ABC or ITS to XYZ, etc. NASA uses a point system, check out more at http://performancetouring.com/ You can use the point classification form in the rules area to find where you fall. Unfortunately the forums there are all but dead. I run ITS for example and fell in PTC, with some work I got to PTD. I like NASA in TX as our SCCA regional program is weak, I can't speak for other areas of the country. I am currently doing both NASA and SCCA with no changes between organizations other than some racers tape over the others decal for the weekend.