I believe all the Gen 5 stuff will change the inter cooler placement(on top of the blower for less heat), so would expect that would add some cost over just a blower. I went Gen4 recently, and I was told it will be the last upgrade from Whipple, that will be available for the 5.4/5.8 GT500s. They could have changed their minds, but lots of developement for a pretty mature, niche market(not like the Coyote). BTW, I have been told my Whipple screams more then whines, but I am running 2 3/4 upper and 10% lower, on E85.