just want to share some experience about KYB shocks, had them on my old 323F BA, they are ace. in fact everyone in the mazda club uses them (or Eibach for the posher ones lol).
buypartsby is the cheapest place i have come across, i did try to negotiate a group buy discount before but the guy was having none of it.
some experience about shocks: all shocks normally are only meant to last for 10 years/90,000 miles, they are wear and tear parts of the car. i wouldnt be surprised if it was the shocks that makes the knocking noise (which sounds like it was from what everyone is saying)
probably worth changing the springs too, as they tend to have more or less the same life expectancy as the shocks.