I'll call BS on that L31, a fool is born everyday but I'm not one. You will not pick up no damn 2/10 at the track from a damn thermo swap. That's not reality. I have spent too many years around race cars to buy that ****. Now I would buy you got better traction and better 60ft to change the numbers that much but nothing cooling related.
And I know for a fact the LS motors thrive at a little warmer temp too, plenty of experience there as well.
Now if your talking a full race application at the track things change a little, especially if hot lapping. But then your dealing with a entire new set of cooling issues to contend with over a street driven daily driver.
Its all based on what is in the PCM programming. Almost every engine I have ever messed with pulls timing when coolant and intake air temps are elevated. When you drop the coolant temp the air entering the engine also cools down which is practically free HP. Finally running cooler also helps keep the clutch fan from engaging. The clutch fan can have a huge effect on ETs as well even if it is not fully engaged. The cooler the engine runs the more it free wheels.
I am not sure what you mean by cooling issues on a daily driver. If the cooling system is functioning correctly, you change the thermostat, it opens sooner and the engine runs cooler, period.
In 90°F weather and that Ram with the factory cooling system it was very much a reality. All runs were dead hook back then in that truck. 5,500 lb truck with stock 3.55 rear gear, stock torque converter and P305/50R20s assured that. I wemt from a 9.8 to a 9.6 in the 1/8th and my 60` was even slightly better from the increased torque and throttle response of the PCM running more timing advance.
The LS engines also run a little better cooler than OEM temps as well. My buddies cammed 6.0L just made 345 RWHP through a 4L80E in 2nd gear with an unlocked 2,800 stall converter.