Quoting 89Patches:
I did the Outlander "Upgrade" on #19 and I honestly wouldn't recommend doing them (Waste of money IMO) But I maybe a bit bias as I mostly road coarse my car and after about 2 laps at my local track the brakes start to heat soak and by the end of the 3rd lap I have next to no brakes. And no I didn't use cheap pads/ rotors....
When looking at Wilwoods for my Colt (one off custom drilled rotors, spacers, and 4 piston calipers), the drop in pads setups gave something like 6 temp ranges.
Your pads likely do not have the needed temp range for what you were using or were outside the useage range, that your rotors were able maintain a heat sink for.
Not bashing, just stating that the Outlander rotors and most pads sets made for it, unless custom (READ heavy metal content with additives to match high temps) and essentially rotor killing style due to excessive wear, it's simply more swept area per rotor revolution that a you will get.
For the street, with an upgrade cold grip and or similar cold friction and elevated friction at higher temps, you will gain something from that setup; as you stated, this will only take you to a point. Everything overheats because not racecar, and not designed for racecar, yet.
We have to remember that these setups are for the street, not the tracks.
Setting aside the street, track setups use higher temp (super expensive fluids), larger rotors/swept area per revolution, rotor killing pads (mostly), and likely more piston area per corner with appropriate squeeze force, ducting, drivers who don't over run the brakes and understand their limits.
GVR4's using stock components can only go so far, as will using the Outlander parts. The Outlander parts do give an increase in efficiency, so a minor win for a decent price.
Did I mention that 2005ish Outlander struts, look very similar to what the GVR4/DSM/EVO/CSM use?
That's another story .... sitting on my garage floor.