No, Actually I have decided to go ahead with one amp istead of multiple... Thats why I have skipped an extra amp for my sub.
By the way, I have installed the amp today. There is strange situation about gains of the amp. I have decided to play safe for the amp today. I use multimeter, 1khz and 50hz sine wave signals for gain adjustments. I set the gains for Channel A to 18v output while as for the sub channel I set 34V. The idea is getting 2*80+300w rms from my speakers ... Now the gains are set to %70 for mid channels and %80 for sub channel.It seems pretty high for me, because I am not even using the full power of the amplifier yet.. but the gains are so high at the moment.. The preout voltage of my HU is 2v ... I think there is relationship but now %100 sure about that.. What do you think ?