You need to reference the official Improved Touring Category Specs (ITCS), available on the SCCA web site. I don't have the url handy.
Part of the confusion on years might stem from the practice of listing ONLY the specific model years requested, and NOT updating them to allow follow-on years even if the specs are the same.
For example, the 1993 Golf III was listed in A when first requested but it took a separate request to get the 94-97 years added to the spec line. Newer ones are now legal (with the 5-year-old rule) but haven't been added: Even though a '98 Golf 2.0 is the same as the '97, it isn't expressly legal.
K