Originally Posted by CFZ

I prefer monotube suspension over twintube (KW).

Basically an external reservoir is there to be able to hold more shock fluid, for temp reasons. Most of the time however the shocks with the external reservoirs have multiple adjustments. if it is a 2-way then it is compression and rebound. If it is a 3-way then one would adjust rebound, one for high speed compression, and then one for low speed compression.

If you're only looking to go lower. Then one without a reservoir should be plenty. And those are typically one way adjustable, the quality one way adjustable would adjust only rebound, but some of the cheaper makes adjusts both compression and rebound with one knob.