A positive result may be out of reach, but a positive performance isnt...
I expect the opposite actually. Positive result but not a convincing performance. Kinda like Arsenal-Juve.
Manchester will be missing almost all their stars (Ronaldo, Vidic, Rooney, Carrick, Hargreaves etc) and all the players on their bench are from their youth team. If i'm not wrong, Scholes, Giggs, Neville aren't well prepared physically and they can't play more than 45 minutes, plus Ferguson implied that he'll give a fair chance to all the available players.
We on the other hand will have the final test before CL and Ranieri said that he won't make many substitutions (i think we'll play like it's an official match and we'll make only 3 subs). Being the final test it's logically to expect the best players to play on this match and i think that our best players certainly aren't inferior to Manchester's B team.
Just like vs Arsenal i think we'll take advantage of our experience (their inexperience) and possibly win the game. But i'm not so sure that we'll perform well.