in reply to Plug-in architectures
Sounds like a pretty good idea to me, however i have to wonder: why both tar and gzip? It seems to me that your goal is just to get all the information (files, manifest, etc) packed into a single file, and tar works fine on its own. gzip will give you smaller files at the tradeoff of the time it takes to uncompress (and recompress?) them. So unless size is a major concern (probably not when dealing with perl source code), i see it as unnecessary.
You could also consider that there's no requirement for your files to end in '.tar' if you're using them solely for the purpose of acting as plugins for your program. if you give them a more distinctive extension (.ppi for perl plug-in?) it will take some of the guesswork out of figuring out which files are plugins and which are garbage in any given directory.