Neymar's had I think 3 30+ goal seasons for Barca out wide, last year all of MSN got over 30, I *think* Villa managed it under Pep from the left too, and I think all 3 of Pep's front line got 30 in 08/09 too, if not very close.
In 13/14 Aguero, Negredo and Dzeko all got over 25, so it's not like the numbers are impossible in England.
I don't think it matters if he plays centrally or not, he's going to get in the area and he's going to get a lot of goals.
Aguero probably unlikely to go 2 full seasons without an injury too.