The debate about going strong or weak is a bit vague, for it is not clear what strong or weak is supposed to mean.
It's one thing to make 2-3 changes, another thing to make 5-6 changes, and yet another thing to make 7-8 changes.
Pep made 6 (!) changes vs Spurs after a very good performance vs Villa, and we battered them at Wembley. He made 8 changes vs Leeds and Chelsea, and we lost. Think 5 changes involving the likes of Laporte, Cancelo, Rodri, Jesus and Sterling won't make us significantly weaker, if at all, given that they will be fresh and desperate to show they have the quality to start in Istanbul. But another 3 changes, e.g. Steffen, Mendy and Torres, would be too much.
Pep is loyal to the legends who helped him succeed at City, so he will start Aguero in some games. However, Aguero can't press as well as the other forwards, so I'm not sure Chelsea is the right game for him, provided that we want to seal the title and see how they cope with proper pressing. So, I'd go with Jesus/Sterling ahead of Kun. He will get other chances to start.