My cousins truck I just finished building a box for. Its only running of about a thousand watts right now, gonna upgrade soon. I hate this song but it gets pretty loud.
Email the retro fit source and they can answer any questions you have. To answer your question about what holds the projector to your headlight there is a threaded end on the back of it and you get a nut and screw it on mad that's how it is attached.
I just put the dimensions in on the Torres Box Calc. and I;m coming up with around 4.3 net cubes after sub and port displacement. 4.3 cubes isn't enough space for 1 15"?