Replacement sub for UCF11?

Hey guys, I'm trying to find a suitable drop in replacement for my factory 8" sub that has blown.

I want to stick with the IB/freeair setup, but with the huge range of subs available, it's hard to even think of where to start looking.

I know there's an article on clublexus/lextreme, but it seems that that model sub he used is discontinued.

Any help is appreciated!