Vista SP1 - Get more free space after installation

I recently applied Vista SP1 on my laptop running Vista X64.  I must say that I noticed the improved file copy performance, although I also fully appreciate the changes made to it as nicely described in Mark R blog here:

I also noted that my available free space reduced by quite a bit after the install.  I came across this reference:  that allows the removal of archived RTM files.  The CAVEAT is that after you use this, you will NOT be able to remove SP1 from your system.  The tool is really straightforward to use, and it freed around 1Gb of space from my C: drive, not bad for commiting to SP1..