I have no idea, considering we still didn't get any official numbers from PD. The fact that we are still waiting probably is a sign that GT:S probably underperformed a bit. But let's wait and see.

By the end of this year:

Forza Motorsport (3 games) ~ 7 million

Forza Horizon (2 games) ~ 8 million

And we most probably will have a third Horizon this year pushing the total to ~17 million.

Note: These numbers are just my estimations and not supported by any real number s as Microsoft doesn't share any software numbers. 

Safe to say now if it does outsell Forza it will be on brand name alone and not quality lol.

How well does Forza do in Europe? Have Horizon sales eclipsed Motorsport?

User moderated - Bristow9091

Forza Horizon 3 is doing miles better than Forza 7 in europe.

This isn't going to happen. This isn't a mainline GT. It's a prologue no matter how PD try to spin it. I think this game is born from Sony putting pressure on PD to release something.

Still hasn't outsold FH3, this prediction is way to unrealistic

nah it's ahead of fh3 , that's just projection imo 

but all games , outselling all won't happen

?? FH3 is currently showing up at 3.15 mil on the charts while gts is at 2.58 mil. At the rate it's selling it will outsell it took way longer than what most expected, I remember seeing people saying it would outsell it week one lol. 

Those poll results...

Highest selling GT ever.....yes. Beating all Forza Motorsports combined? Yes. Beating all Motorsport AND Horizon games combined?! Never ever.