I downloaded SP3X June25 (http://sketchyphysics2.googlecode.com/files/SetupSketchyPhysics3x-Jun25.exe) and on Sketchup's startup i get this error:
Error Loading File sketchyphysics.rb
No such file to load -- SketchyPhysics4/SketchyPhysics4.rb
but then everything goes normal, and I see new features like density,but i cant find destroy function and some other outlined in topic "Working on a new scripting system".