Automatic ECU question

[JoeC#3]

prolly wont get much help with this but becuase my car is an auto...thats mostly why i chose to go with all show no go.....but when i stomp it on the highway and get up to 100 it shifts into over drive and wont let me go any faster....is that becuase the ECU is tellin it to do that or is that just its top speed...i dont think it is but i was hoping to hear that a new ECU would change that but im also not sure if i can find one for an auto....thanx