I'm a bit confused with all this. I have one of those beautiful K-Line B&A Berkshires, and it came already equipped with TMCC. I was not aware that the model came any other way except with TMCC. Granted, the model is beautifully detailed but, sure will NOT pull very many cars, since it has a very small motor installed in the boiler instead of in the firebox, as all other steam models are.
Personally, I wouldn't waste my time with this model, as beautiful as it is. I'm pretty sure the Legacy version by Lionel, corrected the "undersize" motor issue, but remounting a much larger motor in the firebox, where it should have been in the first place when K-Line made it.