Q: is its function limited to speeding up the downloads from PSN?
A: The function should not be limited, and downloads will reach the same speed your PC receives, some people may notice reduced lag in games like Modern Warfare 2.
Q: if it's possible to swap in pkg files from my PC, how is it done?(the procedure)
A: The application will automatically, take the PKG from the downloads folder when your console requests the file for a second time (Download on the manager must have completed first, for it to do anything), this however doesn't allow you to swap the pkg file with a fake alternative, as an error will occur on the console...
Q: does it support "Life with Playstation"? I'm still on 3.15 and i can't go online (I use linux with my ps3 and I didn't want to update)
A: You may notice a slight improvement in Life with Playstation, and even if your running firmware 3.15 it will still work, however you'll need a way to bypass the firmware update; so you can access the Playstation Store.
3.17 update fixed the crash on download completion error!
That's great news
, thank you for letting me know...
Like WasteWare says download PSN DM 3.17 and make sure to include the correct information in the Country.txt which should be &country=eu for spain.