Achieved 2:58 with the Silver Bullet, because if I was going to kill two unstable Mobile Armours it'd be with as much kill that could be packed into a Gundam in all but name as possible.
I did actualy change the loadout for the bosses. Firing Program LV3 & LV1 Mele Program LV3 & LV1 Anti Beam LV4 & LV3 Anti Melee LV4 Strengthened Frame LV1
I wanna know how people getting 1 minute other than hacking? Fastest I could do was 1:43 with the Galbaldy Alpha HiMo. And I was literally on their ankles like gum or a small angry Chihuahua.
That is more for avanced players, a more reliable and pragmatic solution is just do it with affordable lv1 Super Gundam with lv 1,2,3,4 ranged mod parts.