It isn't the be all and end all I know but, Teixeria is a far more technically able player than Cuadrao. Whatever he might turn into, I don't think it would be Juan #2.
Whatever he turns out to be could result in £30m down the drain. I would prefer to spend a smaller amount on Mahrez. Younger, arguably the best player in the Prem so far this season and would be less of a risk.