If I recall correctly they were VW 411 coolers. The temps we're always at the thermostat set temperature about 195 degrees unless I was really driving it hard and it might have crept up to 220 maybe. I know I never had an overheating issue.
The only thing I would consider differently is to use a hard GT line set-up running the length of the longs instead of the SS flex-line I used. I would also likely use rubber lines, like the factory oil lines on a 6, for the remainder of the system. Mostly for aesthetics and any noise or vibration.

It's funny this old system came up now. I am just getting ready to re-do the thermostat location on my current car. The thermostat is in the frunk and it belongs on the firewall on the passenger side. So we will be relocating it and then making new rubber lines on both ends of the hard GT lines.