Your math doesn't quite add up here.
200hp/40lbs = 5hp/lb
Your corvette data (sounds like a nice car!) shows that you got 1.25hp/lb, which is still very respectable.
6lb per tire = 24lbs
30hp/24lbs = 1.25hp/lb
You're right, it didn't come out to 5-6hp per pound of unsprung mass that is suggested you gain. I imagine there had to be some diminishing returns somewhere? But, there is a gain in power. I was super skeptical that it would register more horsepower at the wheels.
Of course there's loss though from the crankshaft to the rear tires on any vehicle. I keep using the corvette as a reference because I know it so well lol... Chevy claims 505 hp on the stock ls7, I saw somebody pulled one and it dyno'd 510'ish at the crank, then in the car at the rear tires it dyno'd at 440'ish, so it was around 14% loss through the drivetrain.
If the theory was accurate on the vette, if I were able to lose 20 pounds of unsprung mass at the rear wheels, that's 100-120 horsepower... so, taking the weight off in theory adds horsepower beyond the power at the crank... which is defying physics lol...
So there's definitely some more to the theory than just the 5-6 hp per unsprung mass removed. Now I want to go look those theory's up lol... I'm curious where the number comes from.