I have seen people do both. Mine is above if I remember correctly, and no issues in over 20K, but I definitely considered the same. I think either way you are good.Installed J&L catch can before running out the door on vacation. I routed the line into the PCV as they show. The intake I ran under the wiring harness for the cam phasers, etc instead of on top. Seemed less likely to rub and cause a problem long-term.