Help with replacement sub driver

Hi Guys
Just wondering if anyone has had occasion to source a replacement 12" driver for the D-Box David 301 sub.
I was given one and the driver is done but the amp works fine.
Hoping to save myself some time doing all the reading and calculating as I'm not exactly a speaker guy so I thought I'd ask if someone has already done it and what they might have used.
Not looking for anything exotic, just like it to work OK with the box.
Something like the MAD 1259 would be the max I could spend($150).
A lesser driver that matched the box would be OK too.
Thanks
Hugh