It would be great to have Cavani. And I'd say 30m would be a fair valuation, but to make a fair deal out of this for everyone involved, I'm going to have to say that tripling Cavani's salary is a bit much on part of the club. Going from 2m to 4m is a fair jump, and while teams like PsG and those in England would give him a fair raise, we will find that a majority of those already are covered in his position. So while it's great to be chasing him, I think we can be better at negotiating his salary. Also if Napoli is open to dealing for him, I think Juventus will choose Cavani over Higuain, Dzeko and VanPersie.
As things stand, it would be a bit much to lose Matri and Gio in is deal, because Gio is going to be an interesting commodity post the Euro, and I'd rather use him to help us get to Jovetic if that's a possibility. 20m plus Matri is worth about 32m or so, and that would be a fair estimate of Cavani's worth at this point in time. I'd even push that up to 35m, but if we are intending to spend that kind of money and pay him a 6m salary, it's a fairly expensive deal IMO, when there are fairly decent alternatives out there. I'd personally like us to get two big players up front in a CF and RWF. A Cavani like deal may not allow us that.