The H&S Performance Black Maxx has been a pretty good seller for us for your 6.4 Powerstroke. We have received great feedback from customers who are happy with the increased power, mileage and features of the Maxx.
Rollin Smoke Diesel. H&S Performance Black Maxx Race Tuner 2008-2009 Ford 6.4L Powerstroke
We have been with H&S from their humble beginnings and we could not be more pleased with their customer service and products they offer.
If you have any questions please let us know.