You should get the Source Unpack : http://wiki.sourceruns.org/wiki/Source_Unpack (Also OoB too works on SteamPipe however some strats requires the Unpack) If you experience any OoB difficulties, ask an OoB runner
No, all versions should be fine. The Unpack that is on the Sourceruns Wiki is always the most up to date version.
No unpacked is more helpful to run because its the old version and the old version had easier glitchs to preform
It's not "unpacked", it's Source Unpack. And as said previously, it's only easier to perform edge glitches and save glitches, not all glitches.
It was recently discovered that it is possible to set your mouse sensitivity to a value so high that the game considers it infinite, leading to several new glitchy techniques being discovered.
The rules have now been amended to ban these new techniques in both Inbounds No SLA Legacy and Glitchless.
