Not on a Soarer, but I've several attacks of the "boot budgies" in other cars - usually been a shock on the way out or worn top hat. Soarer rear suspension is a bit more complex than most though, so could be any number of things.
OMG !! mine is doing the same thing and i thought it was the brake pads! but it only happened when i hit a little bump or uneven surface! how i now know its 100% the shocks is because my mechanic said to me a month ago "YOU NEED NEW SHOCKS YOURS ARE LEAKING AND FCKED" haha
If it's shocks, they are pretty cheap - I got two new KYB shocks (same as the OEM's) for the rear of my car about 4 years ago for under $300 NZD - took me about an hour and a half to fit them - easy job but you will need a spring compressor.
If it's the top hats - can't say as I've never had to replace them on a Soarer - I replaced them on a Nissan Laurel I had once - specifically the seating rubber which had perished leading to squeaking AND clunking - can't remember how much the parts were but it was pretty trivial.
If it's something else like a bush, no idea as they vary so much.
Honestly, i am going to have the car jacked up but don't really know what to look at or look for, if something is broken i could probably see it. Other than that, due to my inexperience and close to zero mechanical knowledge, i doubt i will be able to identify much.
Is there any posts that you have came across that have pictures to what i should actually look at?