With 150 million € + sales to spend, i would aim for a little more than Nani, Romulo and Santon...
Griezmann, Di Maria, Cerci, Osvaldo, Kolarov, Bonaventura/Giaccherini and Gundogan should (very hypothetically) be around 150 + the sales of:
Out: Vucinic, Quaqliarella, Padoin.
That would be a great squad:
3-5-2:
Buffon
Barzagli/Caceres - Bonucci/Ogbonna/Caceres - Chiellini/Ogbonna/Peluso
Licht/Isla/Caceres - Vidal/Asamoah/Bonaventura - Gundogan/Pirlo/Marchisio - Pogba/Marchisio/Bonaventura - Asamoah/Kolarov/Peluso
Tevez/Di Maria/Giovinco/Cerci - Llorente/Osvaldo/Tevez
or when 4-3-3
Licht/Caceres/Isla - Barzagli/Bonucci - Chiellini/Ogbonna - Kolarov/Peluso/Asamoah
Vidal/Asamoah/Bonaventura - Gundogan/Pirlo/Marchisio - Pogba/Marchisio/Bonaventura
Di Maria/Cerci/Isla - Llorente/Tevez/Osvaldo - Griezmann/Giovinco/Tevez
Would give us plenty of options... There might even be to many players, so dropping Cerci or getting rid of Giovinco might be an option. I don't know if Griez could fit in at the 3-5-2 anywhere...
Funny experiment, but unfortunately we will have a lot less to spend, if we manage to keep our good players and bring in one or two good prospects, i will be satisfied. If we land a guy like Di Maria or Griezmann, just getting Osvaldo and Cerci would be a very good mercato. I don't really think we need much on the left side, as long as we play the 3-5-2, but if an opportunity comes, i'm sure the management will consider the options. We might need an extra midfielder for some depth, and i still think Bonaventura would be quite nice, especially if we bring in some leftie like Kolarov or Coentrao (those two are linked to us, right?), since Asamoah will then be at disposal at the midfield more often, which would mean we have both him, Vidal and partly Pogba to play with lots of physical presence.