I would concur that you may need two more amps. The MBL amps in stereo mode do not have much power or current capability at rated output (130/220/340). Peak output is another thing altogether but they really perform their best as monoblocks. Perhaps you can combine 8011AM or 9007 for the top and 9008A for the bass? Also, 9011 amps in stereo mode will still face the same problem as your 9008as. If you examine the rated output the 2 amps used in stereo mode are almost the same.
I had overbuilt 100W Class A amps on my MBL 101E speakers and while I knew they were not able to drive the speaker adequately, this became clear only after I installed amps with much more power.
I had overbuilt 100W Class A amps on my MBL 101E speakers and while I knew they were not able to drive the speaker adequately, this became clear only after I installed amps with much more power.