He has the 25% under drive and the smaller damper (6" IIRC). IIRC they have a 6" and 7" damper, the 7" is for very high rpm or very high hp.
It should go right on your dakota just like the ram. You need the special tool(s) also, I think airram rents them if you want to do that, email them they will help you out.
I am going to get one of these eventually as well. I found a dyno from another company(can't remember who right now) that sold a 25% under drive pulley for the 08+ engine and it showed 27lb ft gain. That's huge. Theirs doesn't have a damper though.
Breathing in and out is good enough for me.