Hi, I haven't seen this info anywhere else, does the new 0.90 spec completely replace the 13.3 installer? I think "yes". What about NSIS Portable? I think "maybe", if all you're doing with NSIS is packaging PortableApps, then the NSIS included with 0.90 (it is included, right?) is all you need.
The new 0.90 relese makes the old 0.13 installer and config files unnecessary. You also won't need NSIS or any additional plugs as a build of nsis with only what the installer needs is included. Plus, you usually wont't have to update your config files with new releases (unless you want to use a new feature).
Sometimes, the impossible can become possible, if you're awesome!