porto are unbeaten in the champions league so far this season .
portuguese side beat bayern munich 3-1 in quarter-final first leg last week .
julen lopetegui leading side for return leg at allianz arena on tuesday .
ricardo quaresma was the star man during victory at the dragao stadium .
lopetegui has changed style but club still sell players for big profit .
porto are able to balance books and snap up young south american talent .