Torque Boxes? Do I need them
My non-expert opinion is that you would derive much more benefit from sub-frame connectors than from torque boxes. I say this because the connectors will substantially reduce body flexing when cornering, a lot of which you will be doing on the street. Now, as I understand it, torque boxes will provide more benefit in a car with a high-torque big block and a set of sticky slicks.
However, there are more people on this site that are more expert on this subject.