well i actually have a second battery in my garage :P pretty sure it works

 

A stinger or rockford 1f cap cost 70-100$ ... A 20ah battery cost the same and is a LOT more helpful will providing reserve capacity and is very small itself. If you were to pose the question of a 1f cap vs a small battery of equal value on any of the big audio forums especially diyma which has many expert and experience car audio enthusiasts i guarantee you 99% will dismiss the use of said capacitor to correct electrical deficiencies

 

A 10000 watt amp will probably be a 1 ohm-10000watts or maby a half ohm so u can get subs rated at 4 or 8 ohm which will be a lot smaller for watts. i would recommend a Orion HCCA124 4 ohm sub rated at 4000 watts...