It’s not just the HP Shaky. Its how much HP delivered to the tires. The automatic transmission has a higher parasitic loss then a manual, but you have torque multiplication, and consistency with the auto.

So the exhaust and CAI will gain you 40-50 HP at the crank. The more you push through the stock converter, the higher the percentage of parasitic loss. Dodge knew these would be beat with a race hammer. For that reason the automatic transmission benefits them. Rather then break a part; the converter has enough slippage to buffer.
Ford set excess clearances in the Mustang for the same reason.
This slippage deducts from your HP delivered to the tires. Many transmissions are doomed in the Challengers, due to add on mods. It wont be brute force. It will be heat from cavatation, or loss through hydraulics.

Most will never add enough power to worry about heat in an every day driver. I am building a high profile car, and what ever I can get safely from the stock rotating assembly, I want!