At your mileage your front struts are toast. Though you might not notice the difference as it's gradual degredation of your ride. You will notice a huge difference when you put new ones in. Check out: http://www.shox.com/appguide/shoxshop/productsdisplay.php
The Koni FSD are the rave on the other message boards. It stiffens on the highway and softens on city streets where there are more pot-holes, etc. Also, right now with free shipping. I know that these aren't cheap compared to the Monroe's but you are after all driving a Volvo, and a T5 to boot (personally I would get these with the Eibach spring kit, but that's me)!
On a separate note, shox.com can also set you up with other components like spring seats, strut mounts, etc. Not on their site, so you'll have to cal them.
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1998 S70 T5 Emarald Green Metallic (125K), 2004 V70 2.5T Ruby Red (45K), Previous Owner of Black '94 850 Turbo Wagon (Sold at 140K and miss her). My cars have been running so well lately they've got me worried.