Hi, I would like to help you in showing that this is not required to race in the rulebook. This will save you some money and improve the performance of the vehicle (I'm personally allergic to adding front weight to a nose-heavy car).
I've reviewed the SCCA regulations for club racing and there seems to be no requirement for any car to have front strut bracing in any class.
The keywords used are: strut tower brace, strut tower bar, strut tower stayrod.
Now, tracks may require specialized local regulation to participate. Of course there is no point in arguing against these (as you have mentioned), but also I can't think of any safety reason that a front strut tower bar would be required. If you let me know which track you are planning to run and the type of motorsport (club racing, time attack, hpde) I can look up the local track regulation.