USSRCoder: Technically, do you want to make "Repacks", but only from software, like we do with games?
In terms of precompressors, the result you get depends heavily on whether there is anything to recompress within a given data set. Is there and detectable data streams compressed with e.g. zlib, deflate or not. Classic preprocessing filters, such as Delta, BCJ/BCJ2, are already used by archivers (7z, rar, freearc, etc...) in most cases.
DLZ can bring a slightly better result than LZMA in the final compression, if x86/XP compatibility is important, for targeted use cases.
If x64/Win7+ is the goal, then using the Razor archiver is a possibility, or even LOLZ. It's true, regarding unpacking, it's necessary and recommended for LOLZ, due to the elevated user permissions and the cls filter. (It can also be run on XP, it's true, there's no such problem there.)
It is true that if we have a lot of extra time and insist on squeezing out the theoretical compression maximum available with 7z/arc, without external prepackers/compressors, then using "m7zRepacker" (see
this) or "Ultra7z Archive/UltraFreeARC" Optimizer is also an option. However, the question arises with these tools, is it worth the time invested? (see
this)
For starters, we can also experiment with this (DiskSpan GUI):
https://fileforums.com/showthread.php?t=104507
For such special tasks, i.e. (re)packaging software installers into smaller packages, there is a commercial solution, but there is no publicly available application. In the old days, Netopsystems AG, under its maiden name, and more recently NOS Ltd., dealt with this. Yes, the famous FEAD Recomposer/Optimizer, NOSSO, can be linked to them.