Okay, I know I have seen at least 5, perhaps 10, topics in this forum, all asking what they can do to their car and still be legal for 'X' (STS, stock, S-Mod, et al). I know I have personally responded to many of these requests for guidance. The following link will pretty much answer 90% of the questions I have seen here.
Legal Mods For My Car?!? Note: This page is pretty new, and is a work in progress. There will be updates to the page as errors are found.
Also: You can save this page, and import it into Excel, Access, SQL, etc. (I added another column when I did so I could roughly calculate the $$$ it would cost to mod my car to X class).
Hope this helps
