While I may not be the "Download God", I have been known to download ALOT before.
Some people do download 200-300GB per month without issue. It all depends on *Your Area* and how bad your usage is(or is not) affecting others in your area.
I imagine, saturating you line 24/7 for a month or two, will ruffle some feathers at Comcast.
Not because of actual GB used, but because of degrading performance of others in your area.
Happy downloading!