sundown audio 2500d

OK so here is what I am having an issue with. I have a 15'' RE Audio dual 2 ohm sub that is going to be powered by my sundown SAZ-2500d v.2 The amp has dual positive and dual negative inputs. should I use both? need to run at 1 ohm How should I wire to get the best possable power flow?

ok the reason i say good is because Ive seen some electrical some people have which to me are great! but OK some background on the post i have a sundown Saz 2500 at .5 ohm running four alpine type r 15s in a custom box tuned to 29hz ..at first i had it running off my h/o 235 amp alt an one...

sorry doubble post.

i was looking into ONE 18 inch sub .. but im open to suggestions on what kind of subs to run with this amp? aswell as my electrical system i have about 6 hundred to spend on speakers an custom built box! all help with be appreciated.. i dont like that sissy **** either i need DEEP BASS...