Personally, I'd go with something like this:
----------------------Hart------------------------
Sagna--Kompany--Mangala--Kolarov
----------------------Yaya----------------------
----Fernandinho--------Milner-----------
Navas---------------------------Silva--------
--------------------Aguero---------------------
Irrespective of formations and team selections, though, we're going to have to work our balls off. If we do, we have a decent chance - we saw in the second half of the first leg that they don't like being pressed, and it would be very much 'typical City' to go there in our current form and put in a performance. If we're not prepared to work hard though, it could be a long, painful, even embarrassing night.