964 Normally aspirated cars used a smilar oil filter system as the early cars, the biggest difference being that the filter was first in line out of the engine on the oil's path through the front cooler and back to the engine. Still after the engine though
965 cars used the engine mounted oil filter, filtering the oil on it's way to the bearings, etc, versus on the way back to the tank. I assume to make way for the heater fans/hoses mounted in the rear fender wells.
The 965 had no oil filter for the scavenged oil
It wasn't until the 993 that Porsche installed both an engine mounted filter for pressure feed side as well as a larger filter for the scavenged oil, mounted near the oil tank. - probably the best oiling system yet for their drysump system.
OK, enough oiling system trivia, my real concern is:
Reaper, what are they doing for a front oil cooler setup?
I hope it's adequate! W/ all that power and no engine mounted cooler, you're going to need ALOT of front cooler.
You can fit 2 964/965/993 front coolers stacked end to end behind the opening in your 935 bumper w/ fittings facing outwards, plug the temp sensor holes, run some -16 lines w/ metric fittings ,(or use 30mm mertic adapters w/ AN fittings) and plumb them in series(allowing the oil to go through both coolers)