Do you by any chance have a pic of another car with the pvc port, just to see an actual pic with it, I also have a 4 channel soundstream 940 I believe, I dont know how good it is thou.
I guess your idea of heavy hitting and mine are completely different haha, but the 12in car toys had was really load, it was in a ported box. i cant imagine what heavy hitting means to you.
Any way you can send me some pics of a box i should make just to get a better understanding of the box. Btw any reason not to make a box out of air craft grade aluminum very light.