Poly bushings are never a bad bet, and they are very durable. I have heard of squeeking issues with other types of cars, but no experience with Volvo. As for your clunk, I find it hard to believe that after the struts were changed that a new clunk came from anywhere other than the strut change. I (on my '93 240)changed control arm bushings, sway bar bushings, wheel bearings and struts up front and guess what... I got the 'new' clunk too. Why? The gland nut on the top of the strut tube was not tight enough. I wrenched down on them and ta-da... no clunk anymore. I would not suggest using red locktite as it is a little more permanent than I like, maybe blue would be a good plan. Try to tighten those gland nuts down again, you may very well be pleasantly suprised. I was going to pull my hair out looking for the clunk problem and I stumbled on some posts that talked of the loose gland nut... fixed my issue like a champ. I hope this helps!

Scott