This one came from email discussion with Silvers export manager:
Silvers NeoMax Suspension Fully Adjustable
Part # NM121
Spring Rate: Front = 4.5Kg / Rear = 3.2Kg
Price: RM2650(Malaysia)/35000PHP(Philippines)
http://www.silvers.tw/product_suspension.html
To compare from Tein's Street Basis Spring Rates of Front = 3.0Kg / Rear = 2.1 Kg the Silvers seems to be pretty stiff.
Will be getting this by February during a visit in Malaysia.