You really need to have a seperate download page where users could grab updates *without* having to go through MrPoster. My brother is on a dial-up connection, and considers himself lucky if he can mamage to get a 50K connection. I would want to be able to grab updates for him on eith my broadband at home, or the network at the office, so he doesn't have to try updating on a slow link on his system. Perhaps even provide the adequate update to bring whatever "latest" version you allow people to download directly up to the "current latest" version. This especially includes the category updates, which are sizably larger than the updates for the programme itself.
The problem here is the developers hold the same attituse as eBay's developers themselves; they sit on the same gigabit ethernet segment as the servers, and they think that is a realistic measure of performance (which it most definitely is not).