That part i wholeheartedly agree on, with SS on midbass that will be a bliss.
THat exactly what I`m doing in my own car. sounds terrific in my test closet (shaped as cabin of my 4runner) with brax matrix driving MW 160 and tubes on 140 and 102. 12W single ended each. MOst likely I`ll move up on 650 430 110 in actual vehicle but leave amps as described.
Specially if it's an x4