For those still having a problem. We have created a new build of Impulse that you will need to download and copy in to place that will help us find out why it is forcing a large download on your systems. If you don't mind helping us out, here is what we would like you to do:
1) Download the zipped up Impulse files here: http://sd.stardock.com/impulse/Impulse%20Files.zip
2) Copy these files in to place where Impulse is installed. By default on Win 7 64-bit the install directory for Impulse is C:\Program Files (x86)\Stardock\Impulse. C:\Program Files\Stardock\Impulse on a 32 bit system.
3) Delete the elemental UpdateSizes value here HKEY_CURRENT_USER\Software\Stardock\ComponentManager\UpdateSizes
4) Run Impulse and once you are able to start the download/install, start is up. Once Impulse has started the download (ie. you see the download percentage going), you can immediately Pause or Cancel the install (you do not need to wait 100MB).
5) In the upper right hand corner you will see the ?. Click on that and go to 'View error log'.
6) In this file, each error that Impulse runs in to is added by the date with the error at the bottom of the file being the newest. Paste all of the errors for the date that you did this (we don't need to see the entries from other days).
Doing this will help us get closer to tracking down why Impulse is thinking it needs a 1.9GB update. Again, as the is not happening on all systems, we only need those with this problem currently to try this.
Thanks again for your help.