To be honest, I have never seen anyone with a catch can actually catch anything. This is a race app that is required by some sanctioning bodies. Running 5-10 PSI on the 2AZ-FE is not going to be pressurizing your crankcase. At 9PSI for about 20K miles, I have not seen a drop of oil form on my open air crankcase filter. Much like the air diversion panels and hyrolock bypass filters, it is not really needed. If you want one, install one. It does not hurt a thing. Of course, if your mega boosting, then you just may need one.
