I have the Toshiba MT8, and updated it to the latest InFocus 3.2 firmware, that I got from the InFocus web site. When the projector starts up, it now shows an InFocus splash screen, instead of the Toshiba.
If all you want to do is a firmware upgrade, then there is no need to change any hardware. It sounds like the person who answered your questions doesn't know what they are talking about. If you want to do the upgrade yourself, then you will need the InFocus cable.
I upgraded my firmware almost immediately after I got the projector, so my recollection is a little vague about the improvements. From what I remember, the video noise was reduced and black level improved. There seems to be almost universal agreement on these forums that the upgrade to 3.2 is a big improvement.
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