ningnangnong, of those options, the most cost-effective is to switch to the Folex wheels. Together, they weigh 1.2Kg, which is pretty darn good. However, that will reduce you to 9 gears from 27. Are you in Asia? If so, do you ever come to the US? I would gladly pay you for the inconvenience to bring a pair over.
If you need the gears, the SRAM dual drive system is pretty darn nice. If you don't go Folex and sell the dual drive system for more than the price of the Folex wheels.