I think for SPL u can pretty much use any head unit for SQ since its mainly about geting loud. But a nakamichi used for SPL would sound better than say a Jensen
eclipse 8053, 8454, cd5000, cd7000. pioneer 880prs. alpine 9815, 9835. There are alot of good sq units out there. The eclipse models except for the cd7000 all have 8volt pre amps. That will help the amp not run so hard as long as gains set right.