well, lumina SS is 5.6L so it has no comparison with mazda6(2L) and honda accord(2.4L) engine and power wise, thats a over powered monster. on the other hand lumina SS is very expensive to maintain but i personally didnt like the shape and looks of lumina SS at all. Mazda6 is very beautiful ride, cool luxury interior, confortable drive, very very stable at high speed, we have one Mazda6 2004 2.0 L in sparkling silver color, we did 210 KM/H in that car and it was very stable at that speed, breaking was smoother and steady (though its not EBD and ABS). Accord is good car but i personally dont like that car, also there is no indivisuality buying Accord, i would rather opt for hyundai sonata not even Camry.