yeah 10.6.3 is better, thats what i have as well. the fire-i picture is a progressive VGA uncompressed. this makes it a faster relay to your screen because your cpu does not have to take the time to compress each individual frame before showing it, which makes it ideal for any application that will actually process the video, such as using with jitter. ( thats one of the main reasons why i got one :) ) there is however, in the _firei patch, there is a settings message next to the open and close messages… i believe that when you adjust these settings OR the other settings inside the subpatchers, then this is capable of compressing through jitter. you can choose your codec type in the grab-to-disk subpatcher.
ive attached some more handy documents for the fire-i, in case you dont already have them.