Hi you can try http://www.ortecdigital.com/ . They have a outlet at Sim Lim 2nd floor, called "The Disc Shop". I used them once to burn about 500 pieces and they delivered to my office.
Edit: The company also does CD jewel cover and CD label printing.
Thanks for the input guys. I think it's better to outsource the job to another company to do the duplication. I don't think it's gonna be worth my time to burn 400 pcs myself.
Any other sources you can recommend, guys? Thanks again!