I don't think the summit kit is that bad.
"some posts to fit inside the existing cable and will need some solder plugs for the end of the new cable."
what do you mean?
I used the terminals the kit came with and used a screw and nut to attach the positive wire to the stock wire up front. Yes the box isn't aluminium, don't really know if that is a problem in NHRA or Autocross... but hell we don't have that here.
Anyway, you could always see what the kit comes with and buy that seperately. It's not much anyway. Wires, box and terminals mainly. Everything else if to get the box in place.