sub help

[Team dbAddicts Tahoe]

Hi Guy new here but not new to the seen. I am looking for back up subs just in case I ever need to do recones on my 2 15" sub.

So I am looking for a back up subs that can take lots of power. I got 4 crescendo bc5500s strapped. On 2 15" each amp seeing 0.7 ohms. Would like back up subs to be safe. So I am not down a system when or if my subs ever will need recones.

Also if anyone knows people that could do progressive surrounds let me know.

Thanks from Anthony