Ronaldo will pay by himself the cost of the transfer. Financially IMHO Juventus will not suffer any blow.
He will be 34 soon and he is said to get a 5 year contract. Good for him but I doubt he can help Juventus winning the CL.
I was going to say.
CR7 is a giant brand as far as football, and Juventus now has that big marketing and PR draw, I think they could make back the money just by that alone.
As far as performance, he did come off a season which he had 44 goals in all competitions (not including International duties), I think he still has some left in the tank. But yeah, depending on how Real Madrid responds, it's still a tough climb for Juve to win the UCL, even with him.