I couldn't find a sub grille file on Makerworld that wasn't going to damage my sub's drivers existing on Makerworld. So i found one on thingiverse that was pressure fit and didn't involve using clips and remixed it. Once you have printed it its as simply as just pushing them into the ports on your sub. I do not have a sub 4 to test the fit, will try it soon. 

The only changes made were flipping it upside down so the supports print cleaner, along with changing the support style so they come off easier. It also prints both grilles at the same time. Because of this you will have to have a P1 or X1 printer.