What are the differences between these two? I know the CatchCan catches the oil, but the seperator, sends it back to the motor. And what would be the advantages of each? Just thinking about getting one for my STI.... I was looking at this one... https://www.maperformance.com/produ...parator-multiple-subaru-fitments-iag-eng-7151 The Air-Oil seperator seems to be more appeling, because of the fact that it returns the oil. Cheers!