The FOX really can be set up to be very easy to catch a slide. Go and get one of my set ups from
LFS Car Setups
You should pick a track with a few slower corners to help you practice catching the oversteer.
You have to be quick with the opposite lock - experience with the car will mean you can anticipate the oversteer earlier so just practice.
If you are having trouble with my set you can make it easier to catch the slide by making the following adjustments:
-reduce the amount of differential power locking. This will allow the inside wheel to spin up more making the slide easier to catch.
-add some front ARB - just one or two clicks.
-add 1 click of rear downforce.
These changes will however make the set slightly slower.
Good luck. My
LFS Track Guides page should help too.