Small cheap ripole subwoofer

I want to build a small ripole subwoofer for my office. I had one here for a few days, the classic one with the SLS12 driver and it suited the room very well (not very well acousticly, small and with neighbours). I could get a lot of good quality bass from little power from them without disturbing the neighbours. I was amped with a seperate custom amp (don't know what it was) with dsp build in wit a line out to my amplifier that power the main speakers (small fullrange bookshelfs). The Ripole did nt load the room but gave a very nice low bass. Even in the toilet next to the room i could not hear it (with only a thin but isolated drywall in between). So it looks like the perfect solution for the bass issue i have here.

As the SLS12 already wen way to loud, i'm looking for cheap smaller drivers to use, and came to the GRS 10SW-4, with decent xmax (8.5mm), a relative high qts (0.64) and not to low fs (34Hz). It looks like a perfect cheap candidate for it. I did see how Jazzman designed it and it looks like it could work in a fairly small package sitting under my desk, even with 2 drivers. I'm just thinking on what wood to use. Does this have the same needs as a boxed speaker, or can i use any wood like with OB as long as it's stiff and non resonant? For amping i'm thinking about an icepower module, and i will use dsp anyway on this setup as i'm also want to build monitor-like multiways that will use dsp.

So my question is, is the driver ok for this and what cheap wood would you suggest (birch plywood is ridiculous expensive now down here so last option now).