Proper lubrication and tensioning the cube can definitely improve performance. Your best option is to use some sort of silicone differential oil, such as Traxxas, Lubix, or Lubicle. I would disassemble the cube completely, and use a very small amount of a heavy-weight oil such as Traxxas 50k to lubricate the screws, springs, washers and core. Then, use a small amount of a lighter oil (30k is my preference) on various contact points on the pieces of the puzzle as you reassemble it.