nope, I'm kinda doing the same thing as you soon so I've subscribed =P
mine however is going inside the spare wheel so is going to be even smaller.
From what I've gathered it's basically making a small sub box sound like a big one
You basically get foam, squash it between two grills and theres your aperiodic membrane.
Also if you want you can measure the impedance curve to see if you have too much or too little foam.