Well, that opens a whole different can of worms with Vsonic Ceo saying that all these are fake as Vsonic factory is the only one making the real ones and according to him all those cheap offers aren't it. And I know that when I say these people always jump and say "oh, but mine is the 15 bucks one is the real one coz it sounds awesome", but can't comment on that and don't want to.
And if they are by any chance, the different housings would change the sound as proven by vsd1le and an16, which were also quoted to have gr07 drivers inside.
Yeah, if you do a search the topic was discussed in great length. It has been a while since I read all of the posts, but from what I recall the consensus was that the vivo sounded similar but not the exactly the same as the GR07.
Like you said, the vsonic CEO says they are not the same drivers, but that could be a lie (ie damage control). Regardless, they don't sound exactly the same.
And you're right - the housings are different, which likely accounts for the sound difference. I also remember people complaining about the uncomfortable/ill fit of the vivo (specifically the rotatable nozzle, which is supposed to be their big strength).
The bigger issue with the vivo, was that at some point the vivo fakes started rolling in - so much so that even dealers that WERE selling genuine vivos were selling the fakes without even knowing it. And i'm talking trustworthy sellers like Penon. A similar thing is happening right now with the Xiaomi Pro HD - trustworthy sellers like Gearbest, using official purchase channels, were being shipped fakes without even knowing it. So it does happen. That's supposedly why many sellers stopped carrying the vivo. You can find them all over Aliexpress for $15 or less, which to me is a big red flag that they are of questionable authenticity.
So a knockoff of a genuine using (supposedly) the same drivers, then fakes being made of the knockoff. Only in China LOL.
That's why in my mind, why risk buying a fake of a knockoff, when the knockoff doesn't even sound the same? The OPs budget is $100. Just get the real deal, or at least wait for 11.11 and get the real deal for a significant discount.