OK. Another two cents
My situation. Tomei stroker, GT block, RS's running anything up to 1.8 bar on a stock sump and N1 pump. I dont have a head to sump return line and have nver had a problem. I have been on the track and done 25+ laps, oil temps got up to 130 degrees (Motul 15W-50). IF i was to pull the motor out and give it a freshen up (it has only done 11,000 kms on the build) i would put a bigger sump, pump and head return... only because it is out. Make up your own mind...
My car is 99% street driven and never run into any problems.