I'm predicting a realistic 3.5-5.5 million lifetime. 8 mil seems like a ridiculous prediction for a new IP by GG but we'll see, I'd love to be proven wrong here.

4 - 5m, not a mainstream title.

GG's best selling title is Killzone 2 at ~3 million. FPSs tend to sell better than open world action/RPGs. Far Cry: Primal sits at 2.5 million.

8 million would put it in leagues of Fallout 4, CoD, Uncharted and Star Wars: Battlefront. That's just asking way too much.

Sounds too high to me, unless Sony heavily bundles it (main Holiday bundle in 2017 or something). 5m lifetime is likely and even 6m is possible, but I can't see 8m without heavy bundling.

8 million is a little high I think, but I think it will sell 4 million in its first year, around 6 million lifetime.

Yes of course, but my point is that horizon also has some things going for it that TLoU didn't. So I'm just saying I could believe it if horizon sold close to 8 million. It's not likely, but it's possible. 

Me and a few others said Uncharted 4 selling 10million was in the realm of possibility, and most people scoffed at that prospect. Now U4 will end up selling well beyond 10million. All I'm saying is that with PS4, I've learned to not rule anything out for sales, especially for a game with broad appeal. 

Any word on preorders?
Any guesses on first week?

They are insane, even the last of us didn't reach that on ps3

The thread title should really be changed, SuperData didn't predict Horizon would sell 8 million lifetime. They predicted it will sell 6-8 Million lifetime.

Maaaaybe but i think would have to be heavily bundled (which sounds great honestly) like Uncharted 4 to even reach those lifetime sales, where as Uncharted 4 could have reached that 8 million (eventually) without the bundles.

I think 4-5 million lifetime is more believeable and if the world building was as good as it was praised, it could turn into their next big franchise.