European collected rent as personal booster (3,4)
I believe the answer is:
ego trip
'personal booster' is the definition.
(a boost for one's ego)
'european collected rent' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'collected' becomes 'got' (get can mean to collect).
'rent' becomes 'rip' (rent can mean a tear in something).
'e'+'got'+'rip'='EGO-TRIP'
'as' acts as a link.
(Other definitions for ego trip that I've seen before include "Experience enjoyed by the conceited" , "Self-important action" , "Activity boosting one's self-importance" , "Self-centred journey?" , "that involves swelling of head?" .)