I've got a 5BST and a pair of 3BST's in my seconday A/V system (6BSST and a pair of 4BSST's in the primary system).  I'd like to replace the pair of 3BST's that power 4  surround speakers (M&K SS150's rated at 4 ohms), with an 8BST to free up a little space in my room.   The manual and spec sheet doesn't mention if it can run all 4 channels into 4 ohms, however the manual does mention the 8BST uses the same amp sections as the 5BST.  My 5BST powers my 3 mains (M&K S150's rated at 4 ohms) with no problem.  Please clarify, thanks.