Goh .. thanks for the tip as I almost place an order for Water General Mfg Co 6 stage RO+DI from Filter Direct at ebay for US$115 excluding shipping of US$80. This works out to be approx S$320.
Total cost of the TWP is about $110 then it is a good buy!
Since the TWP is a proven by Goh & Sotong Ball then will get one from PetMart tomoro as they are closed today.
Also thanks to Sotong Ball for the tip ie having a slow n steady low flowrate from the tap.