A fuse acts as a weakest link in the chain...even though you have 2x 200amp fuses, that will still only allow 200 amps to flow through the cable. 200 amps is not enough to supply power to that Banda amp to deliver it's (supposedly) rated power of 3000w at 2ohms. The amplifier's 4ga (+) and (-) inputs are not sufficient to handle that kind of wattage at the amp's efficiency either. Basically, the Banda amplifier is not suitable for a typical car environment and probably won't deliver what you are expecting from it.
Watch this...