Everything takes up about 1GB, but most people don't have a need for 3.2 & 4.1-4.3 System Menu's of all 4 regions, and those system menu's alone take up about 330MB. Not to mention all the other duplicate region files, e.g. most people don't need the internet channel for all regions, just one (if that). And there are other files most people don't need, so if I had to estimate the temp folder size for the average ModMii user it's probably about 400MB, give or take 100MB. And those are all files that you woulda had to download anyway if using some other stickied guide. AND you can always delete the temp folder if you really care bad enough to recover about half a gig.