Welcome to V8 ownership. Follow the line back to where it meets the car -- tucked under the eBox on the return, by the heater valve on the send and undo the hose clamps there.
Torx screws are actually able to take more uh...torque...than any hex head. I know, doesn't seem to make much sense, but there are reasons for having them there. Smart of you to buy new ones to replace the stripped out ones; use antisieze when reinstalling (yes, I know -- it's plastic).
The PCV plate can be a bear with those things. I've had to cut them out with an angle grinder -- the plate is being replaced anyway.
best, whit