snuvet75, I ran 7k in my diff but have swapped back and forth with 5k and 7k. Car feels about the same with either, lap time was faster with 7k so that's what I stuck with...
I ran my car outside one weekend (box stock) with Pietsch setup from the ETS race where he made the "A". The car seemed to have good corner speed which normally is a sign that it's not too stuck.