I think at that point they're all kage level. Naruto is a perfect jinchurriki and a perfect sage, Sasuke is an incredibly skilled and versatile individual and has the EMS, and Sakura has unparalleled strength and her byakugou seal. They've all been friends for a long time and each one has a deep bond, so I think they'd have a lot of unspoken teamwork happening. I think the three of them together could take any of the five kage, and just about any akatsuki member. Kisame might be trouble, and so would prime itachi and especially prime nagato, but I think they could power through it