I think you could, if the values I'm guessing are what actually limits the download speed. but it would then also change the bandwidth cap for connections in-game, which might affect performance. try and see if it works, settings are in killingfloor.ini under [IpDrv.TcpNetDriver]
MaxClientRate=15000
MaxInternetClientRate=10000
these default values are already plenty for player data through modern connections in this game, I'm not sure what would happen if you were to increase them even further for something like a file download. probably just easier to set up a redirect, you can get 1GB free space that downloads at 100kb/s from fileden.com.