[Mitch Leland]

I'll chime in on this, I have 3 radiators on my 966 C4S, now C42. I had a taller ring and pinion installed, in 6th gear I'm showing 80 MPH 2,375 RPM . My temp at highway speed never gets over 190 degrees even in 100 degree temps. However my oil gets hot, at the same temps it will go to 260 degrees. Am in the process of looking into an oil cooler.

I noticed that pulling a grade in 95-100 temps that the oil temp rises quickly. I just returned from 4,000 mile trip in the car so I had lot's of time to look at all of this.

Bottom line, unless you're going to drag race your car, I would go for the taller gears, changing the ring and pinion changed all of the gearing, expensive, but well worth it... At 70-80 MPH my car is quieter than with the 3.6 engine, mostly because the RPM's are lower.