What next?

[adulbrich 5,000+ posts]

welding cable..

 

[nowhere 10+ year member]

You would have saved about 40-50$ building your own kit and by using welding cable, plus your would have left over for you big 3. But you probably would still need to pay your installer for the labor. So basically, almost the same amount you would have paid now, but you would have gotten more for you money.

It was a good idea to just do the 1/0 run now, so you not have to redo it later. Also adding another w6 later on down the road would not take more power. Right now you are over powering that sub. When you add another sub you are just going to spit that power you have on tap.