Blind tested Andrea Bocelli Amore CD for both the $11.90 Singapore Version and the normal $21.90 version. No difference in quality.
Personal view is this. If that CD is by a singer or artiste that you support or you value his/her vocals or music arrangements and stuff, its better to buy the more expensive one. If not there will always be this question lingering in your mind when you buy the $10 bucks one, " would Mr XXX sound better in the other CD? Would the soundstage or instrument sound better in the $20 CD??"
But if it is an artiste you just wish to listen to and not much emphasis on the songs, the $10 type of CD will suffice and make you a law abiding citizen.
Parallel Import CDs are totally legal as the Copyright Law has the Exhaustion of Rights Principle. Meaning if the CD is sold in China, the company has no right to enforce that the person only listens in China and cannot resell the CD to other jurisdiction.
So feel free to buy China CDs if its just for trying out the songs or adding CDs to your collection. The singer still earns his/her royalties. No worries.