Scotty isn't really a fan of small turbocharged engines as they are under a lot more stress than one with no turbo.

I personally think the Foresters are pretty good cars BUT I would definitely have a mechanic do a pre-purchase inspection. If it is an automatic, that will be the weak point to lookout for.

Foresters can be good cars, but here me out, NOT this one:

https://www.carcomplaints.com/Subaru/Forester/2015/

This engine is infamous for going through oil like mad. The CVT transmission is particularly weak and the turbocharger doesn't help the reliability. I would look elsewhere.

At least it's not a really tiny engine like some of the newer ones and as far as I know a 2015 model won't have GDI. Be aware that the turbocharger is a wear item and adds more complexity to the engine, but it is a mature technology and can last a long time with proper maintenance. If it's an automatic transmission the CVT is the weakest part of the car, and it will be under more stress due to the higher output of the turbocharged engine. Have a mechanic check the car carefully.