Wanting to add a 2nd sub to my truck. wat setup would i need to make sure its is powered correctly?

currently i have one Kicker L7 dual 4ohm with a 1000w amp. i did the 'Big 3' rewire under the hood, i have a capacitor (which im planning on replacing with an actual 2nd battery), a heavy duty battery. im looking to add a 2nd L7 and either 2nd amp or one 2000w amp to the system. i have a 1998 explorer v8. should i do anything additional such as H/O alternator or such, to ensure the system is properly powered? thanks in advance.