BDD451A is used mostly on a N/A car.
The BDD451A2, which is the one I have is for the AMG.
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.:

SOLD

 

Will this fit 2010 C350?

 

I tried to find that info and did not find it. I don't know if it will fit and work if you can find the part # for the C350 and cross it to this # you will know. if it fits or not. jim

 

bump for my great price change $200.00 with free shipping within the us.

 

I'll take it for $150.

 

which model is this? 1st gen or 2nd?

 

Will this work for 04 SL 55?

 

sold thanks everyone for your interest. jim