BDD451A is used mostly on a N/A car.
The BDD451A2, which is the one I have is for the AMG.(SRT6)
The difference is the BDD451A2 is less aggressive and is made for the AMG,( because the flyby wire is faster in the AMG car) but it will work on the N/A.Actually giving you more control, the BDD451A, on AMG, I am told ,you can not leave from a red light without spinning your tires.

I will take $200.00 + $6.00 shipping.for it. jim

here is from a old post from another site.
I have a sprint booster model BDD 451A that I'm using on my C32 and it's a little touchy for my taste. It's my understanding that BDD451A2 is a more mild version built specifically for the AMG.: