HI Edwin,
When I first received this Double 12, I tested it with a Series I in mono mode with both bridge and neck pickups next I tested it with just the bridge pickup. In my opinion if you do not push the SPL and transients peaks it is suitable for stereo playing with a Series instrument. Nice definition in the higher spectrum and nice lower and upper midrange character (growl) . But I would be very cautious about pushing the lows. It sounds really nice with guitar full range . The 2 k140's in mine are 8 ohms each , I have them wired parallel to make a 4 ohm load.