Really, you can get any of the drivers they have on their performance chart, but you are correct. The ones that have the highest cone excursion would get my vote, and will once I decide to pull the trigger.
https://shop.gsgad.com/pages/performance-comparison-table
Plus, if
@Danzilla31 decides to get one, I can demo before I buy
I'd be very interested to see what
@shadyJ thinks about this DIY option. You could always go the alternative route like
@NINaudio did and get the simple dayton box that will still get you excellent performance, but not lower than ~16hz from what he says.