USSRCoder: The question is a bit confusing... Why do you need an LZMA recompressor if the files in the installer can be extracted from it simply by installing it. Or are these files also available from a separate source, which are also in the installer?
Technically, there is an LZMA recompressor, but it is mostly suitable for compressing LZMA-compressed archives created with 7z to a smaller size. (avg. 1-3% size reduction) I don't know if it is compatible with INNO archives.
https://nishi.dreamhosters.com/u/ <--- see this lzmarec_v*.rar/exe files.