Tell us about yourself!
Be aware, there's an inherent instability in three wheeled vehicles and a reason why their sale has been banned in the US. It doesn't look like that'll be an issue here, but it's good to keep it in mind.
I figured that was the case, it's also large enough that catching a leg in a rear wheel is unlikely.
And hints on calculating a resonant chamber volume? I have a pair of 4 Ohm car speakers that led me to searching for a project to use them with...the digital parts of this project are well within my skillset, but the acoustics aren't something I'm familiar with.