Ok, lets check it out, first I will add that I have underdrive pulleys, this test was done on a stock 5.0 and it worked but was not mentioned was the real world, charging and cooling issues were not addressed. The real world is there can be (I say 'can be' because there are workarounds for these issues) problems when sitting in traffic at night in the summer time with the ac on.
Ok, so you don't sit in traffic at night in the summertime with the ac on. Because you can't. The temps will rise and the voltage will drop. Real world.
I mentioned workarounds, now you are installing electric cooling fans then a 3g alternator. Well you did accidentally gained a few more ponys. All's well. Most of the time.
Was the $60 bucks worth the 16hp and 17 lbft at 5k.
Real world driving is at say 3200 rpms where the gain is 7 hp and 11 lbft. Not so much now but some.
For some it works, for me it is marginal.
Now you can make an informed decision.