If you run a center diff I would run 500k oil. I tend to like the slipper because it's more mild into turns (the front tires can't free-wheel relative to the rear) and pulls better/easier to control going out of turns.

The main things I did at this race was the A-plate kickup, and the front inner camberlink I raised to the upper hole which transitions more weight to the front tires to carve through turns.

Also most people have not tried the 1.5-1.6 split pistons in front but again I ran them vs. 2x1.6 and the firmer valving was faster and easier to drive... it feels slower but lap times are faster because it does not scrub speed in the turns.