According to http://tieba.baidu.com/p/2894913260 the soundsignature of the models should be close to:
VSD3: Shure SE535
VSD3S: Westone W40
VSD5: Sony EX1000
Iam not sure what the infos are worth as it seems, random people replied to one guy asking about the soundsignatures
That is also what the Vsonic CEO claims so probably the infos came from him.