I was looking for a free compression formater for RAR and found 7-zip, an open source product.
As far as I can tell, there's no reason Image-line couldn't use this. (I might be wrong on that). The average Sample fusion zipped pack can be reduced to about half its present size (under the Ultra setting).
The smaller download would be good for the users. I don't know if it would improve your bottom line halfing the user downloads? (1 gig instead of 2)
You can check it here.
http://www.7-zip.org/
Sample fusion 7-zip?
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