squeak are normally something that is bush / rubbing related.
knocking normally is something metal to metal / or damper internal (hydraulic knock)
You will need a little search to find out where the noise is from, fixing the noise is the easy part.
The 86 (like the Subaru Impreza suspension) have a known history of making noise in the rear suspension.
That is one reason the MeisterR ZetaCRD coilovers an OEM style rear springs with a rubber insulated press steel rear top mount to help absorb some of the noise.
For race car that don't care about noise, then a aluminium top mount that use standard 62mm / 2.5" ID springs can be use.
Just something to look out for when researching coilovers.
Jerrick