i cant help with hilux info but for me, the s13 setup although single piston worked really well on the track in my ute.
what are the s12w calipers? they look like twin piston? or are they 4 piston? maybe they'd work better again?

i think choosing vented disks over solids is the more important choice to make for a track car...
your braking performance will vary on caliper choice but no brake setups work well when they get too hot