@Teddox
In general:
Removal of parentheses with content
$puts(spacer,$strchr(%title%,'('))$trim($left(%title%,$sub($get(spacer),1)))
Highschool Lover (Theme from the Virgin Suicides) → Highschool Lover
Extraction of content between parentheses
$puts(char1,'(')$puts(char2,')')$puts(tag,%title%)$puts(spacer1,$strchr($get(tag),$get(char1)))$puts(spacer2,$strrchr($get(tag),$get(char2)))$trim($substr($get(tag),$add($get(spacer1),1),$sub($get(spacer2),1)))
Highschool Lover (Theme from the Virgin Suicides) → Theme from the Virgin Suicides
Further info: Titleformat Examples.