bumper_au wrote:may be a stupid question, but i love the idea of the speaker recess, thinking of doing it to my van, would it need to be enginerred by doing that???
Technically yes as you have altered a structural member but in reality if it's welded in then it really wouldn't weaken the area to any great degree.
Hey Bumper Au . it doesnt weeken the main structure of the firewall ,BUT you should aways ask the question. mine already had the holes from previous owner, with speakers covered in rubber sheet. i think my set up is safer an tidier
P.s Ratbox checked the window tonight and your right half a turn