i honestly have not a clue what those wires are (tannish ones) the are unfamiliar to be from previous times.I was going to run a dist block but since the 8g was (carelessly) installed i figured i would take advantage of free wire. I have always been against caps (beleive in high amp alt) but as always thats prolly gonna change and i will run one.Due to the lack of being able to find higher amp alts for the mark. Its crazy how expensive they are too (caps)
A cap and an altenator have nothing to do with each other. A cap is like a battery that has an uber high discharge rate. High/low output alt will not affect the stereos output only how long it can do it before its taxed the battery dry. With the power wire you ran you wont have a noticable power drop for up to 400 amps worth of draw, additionally if you did a gel cell then that would help but only a little as it can discharge faster then a lead acid battery. BUT if you have a lead acid batter that has over 800CCA then it dont matter anyway.
Caps were popular before class D amps came out. The reason why is a 1000 watt amp could pull 200+ amps for a split second for deep bass transients and the cap would be able to dump that current for about a full second so the amp wouldnt clip and you would get a more solid kick.
With class D amps 1000 watts will only draw around 90 amps at peaks and your power setup can easily handle that.