Just to comment on your Cortex breather. I bought one along with my Watts. I removed an above-axle catch tank and found out that was a mistake. My first event was at Watkins Glen with 40 min sessions. I puked diff fluid out of that little Cortex unit every run. It was removed as soon as I got home. I reinstalled the larger catch tank and didn't have a problem again. The real solution is a diff cooler which is getting installed this year. At the very least you want a set-up that allows the fluid to drain back into the diff once it cools. Some use a breather mounted inside the rear compartment but I prefer to keep the tank outside the car. If you are going to seriously run the car at longer, high speed tracks I think a diff cooler is a good investment.