It is summertime in Texas. It will be hot if you pop your hood after the afternoon commute regardless.
Trying to ram cooler air into the front really isn't going to help unless the hot air has somewhere to exit and carry the heat with it. I doubt a NACA duct or TSIs are going to help your pinging problem in the slightest.
Have you ever adjusted the timing on your car? I would think that retarding the timing slightly would have a much more positive effect on your pinging issue without costing you a penny.