OK There is no real negative to do this mod. The oil residue you guys are seeing is the oil vapor which is all over our cars engine internals anyway. Only way to get rid of that is with a catch can. The diverter valves do seem to be leaking boost or just open when the car is idle in park? Maybe they are kept open on purpose.
To take the second hose off you have to take off the power wire holding tray thing on the top so you can get better grip I used a flat head to help me get more leverage and it goes back on easily just make sure you lock them back right.