Concerning earlier questions... Boulekos had no knowledge about the Crossfire. They were not sure if it would work with the XF, in fact. BUT, we all know that we essentially have an M-B 320SLK (3.2 L V6 M-B engine) and, therefore, the Sprint Booster for that engine should work fine. I took the gamble and - yes - it works perfectly well! ...just got back from lunch in the car and it is a new driving experience - no lag or delay, AT ALL! Glad I did it... !