The answers above summed it up pretty much... Bob (BMorgan) and myself, as he mentioned, have done several comparisons. Turned out when we went in for out dyno-tune, that I made 20 hp more than him before tune, hence the spec difference. After tune, he made 4hp more... So from what I can tell, they detune the Crossfire to make it spec lower than the MB. No biggie, in the end, the XF takes to mods and tuning better...