I was in the same boat like you, for a litttle bit more, I ended up buying the nvx 1200.1 and 800.4, they are small, deliver the power, and working on an 80 amp alternator with just a medium size battery under the hood (2010 ford escape) with no dimming. You get 125 x4 and option of 1200 @1 ohm...
Use a male-male and plug it into a female-to female, result= male one end and female the other end and straight, however the length will be approx twice.
Older version is 600 watts, newer is 750 watts, but they take way more than that, if you are interested in the b-stock just call and find out which version. I do suspect its the newer version, but the site have not updated the specs.
Pretty much the same price new every where, SSA Store - Sundown Audio SA-10 Subwoofer
if you into b-stock which is cheaper here * B-Stock* Sundown Audio SA-10 600W SA Series - Car Audio Bargain
if amp have power and does not go into protect , then I would first check to see if I get a music signal to the amp on the rca's, check for voltage if you have a dmm.