fai,
yes, those are the grey color teflon ones. That's the same ones I use in my car. You can also drill the stock ones for the holes to be bigger.
I usually build my shocks so that when I compress the shock shaft in, it rebounds about 1/4 of the inch back out. This shouldn't be a very fast motion, but a smooth and fluid one. If it rebounds fast and all the way out, I think there is too much pressure in the shocks.
Steve Wang