What is the difference between an SFI and MFI rating on an engine description?

I own a 2004 Ford Focus SVT and I am curious to know what the difference is and which would be better, considering my particular model is the only 2004 SVTF with MFI.
Update: well, i finally found a website that is in regards to the SFI vs. MFI question and the claim is that SFI is better. I believed this to be true, considering the Zetech model comes with the SFI rating also, and is the sportiest of all options for the 04 Focus 3dr Hatchback - thanks for the help. Also, the link is as... show more well, i finally found a website that is in regards to the SFI vs. MFI question and the claim is that SFI is better. I believed this to be true, considering the Zetech model comes with the SFI rating also, and is the sportiest of all options for the 04 Focus 3dr Hatchback - thanks for the help.
Also, the link is as follows for anyone else interested in knowing the answer:
http://www.grandamgt.com/forum/archive/index.php/t-26914.html
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