Just wanted to point out that this guy is not breaking the law, you're just buying access to the beta. v1.0 will be released for free on the steam workshop. They did the same with their 2012 mod, and will also do the same for the 2005 mod. This is no different to what other modding teams like VRC and ASR do, you donate to gain access to the beta of the mod, this skirts around the copyright laws as long as the product is made available for free when it's finished.
I haven't bought any of these mods, so I can't speak for the quality, but I just wanted to point out that it's pretty normal for modders to sell beta access, heck I bought into a couple ASR Formula betas myself.
I'm currently downloading this guy's 2012 mod on Steam, I was curious and honestly if it's any good I might buy into the 2010 mod too, but I saw a comment that v1.0 was coming out on Steam REALLY soon, so probably better to just wait.