I am looking for an amp to push 2 12w6v2. I was looking at kicker since I already have kicker powering my mids and highs. I seen a kx850.2 and kx850.4 on ebay. the four channel is a little more inexpensive. Should I go with the four channel and bridge it to the two subs or get the 2 channel. Will it make a big difference?