I'm aware of all of the common options for front struts for the 850 (Bilstein, Sachs, Koni, etc.) but I'm still perplexed as to why VOLVO USA itself lists so many different struts that actually fit the 850. VOLVO USA lists (at least) the following:

part # list price

9173850 $175.05
8612887 $163.95 (supercedes 9140070)
9140072 $106.68

All are available on-line for about 20% off from TASCA and/or myswedishparts.com, making the 9140072 a really inexpensive choice (about $88).

Can anyone make sense of this?

go with the cheapest which are the OEMs, ride will be less jarring than the more expensive units. I just did my wife's 96 850T, and the base unit from fcpgroton are just fine, save your money on a 14 yr old car. Be sure to buy all the ancilliary parts, and bolts/nuts etc. that go with a proper strut replacement. FCP can help if your aren't sure. The whole shabang ran me about $400 in parts using the basic shock, then head off to someone you trust for a front end align. Oh, and by the way, I would be remiss as a safety engineer, if I didn't warn you to be sure you know how to use the spring compressor...

With regards to the spring compressor; yes, indeed! As a former mobile tool truck salesman, I had the grisly opportunity to see first hand (sorry about the gallows humor) the results of all that stored energy unleashead on some hapless fingers. Be very careful around those spring compressors, and treat a compressed spring very gently. You don't want that thing to unleash its' power all at once.

agreed. be careful.