i also have a 2001 prelude SH and i put some Tien SS coil overs in about a year ago and itstarted to have this problem. i just been ignoring it but now its starting to get louder and annoying. its like a real loud knock from the rear right side of the car. well it sounds like its coming from the right side. i measure all the heights on the coil they all look close to the other side. also i been trying to play with the adj. damper but nothing the softer i put it it just feels like im floating in air but the noise is still there and car seems to sway more. i double check if any thing is loose but every thing seems fine. one thing i notice it that that side the tires seem to be wearing out alot faster than the rest. seems to only make the noise when ever there a crack on the road.

 

Sounds like the upper mount is broken.

 

I had the same problem minus the tire wear,and swaying... though the noise was only for like a few weeks then it went away.

 

now that i think of it it could be but the whole kit came with new upper pillow ball mount wonder where i can replace those at

 

I'm talking about where the shock mounts to the car. I've seen a few 90's domestics that rusted out the rear upper mounts.

 

You may have just worn through the rubber that sits between the spring and the mount... They like $6/ea and special order form Honda.