A lot of the install wil be the same files placed in the same folders.
I would not remove SX1 unless the disk is 90+% full, and I planned on installing some other big programs.
Space savers:
make the C: disk pagefile 200 meg, and enabling such on a seconding disk.
disable hibernate: cmd prompt, powercfg /h off
reduce system restore disk use
reduce IE disk use
...