Originally Posted by jarblue

what kind of redline fluid did you use?

It doesn't explain your experience between the different fluids, but i've battled the clutch hydraulic system in this car extensively. Try not pushing the clutch pedal all the way down - only push down enough to engage/disengage the clutch. The master cylinder is really weak and "stabbing" at the clutch and extending the full stroke of the master can let fluid past the interior seals allowing contaminants into the system.