check for oil leaks from the struts/shocks, check for cracking in any of the mounting points and on the springs. make sure the shocks actually compress and rebound, and verify that you have all the parts you'll need, such as upper and lower spring perches, top hats, nuts, and washers.

(yes I know, it's all obvious stuff, but hey it's all I've got)

 

Checking for obvious wear and/or damage is about all you can do...

Not really about looking over the parts themselves, but tips in general:

Check out the vendor reviews here and on other boards. A search will usually produce usable information. While not always representative of their current performance, others experiences will give you an indicator of whether you're willing to trust your hard earned money with them.

The old adage “you get what you pay for” is very true… You may not always find the cheapest price with a larger/reputable operation.

Used parts will likely carry no warrantee at all. Ask up front about their return policy for damaged (in shipment or broken from the start) goods.

Purchasing used parts is a lot about trust: some research up front might save you a lot of grief later…something I learned the hard way from experiences with a certain vendors' STi headlamp & leveler harness group buys.

Brent.

 

I would like to add check for dents, bent spring perch, any modification, and stripped or stressed threads on the top of the rod.

 

check to make sure that they're the right strut for your application. takeoffs can come from both sedans and wagons, and they're differant lengths. it's not as big a deal with the spec-c hardware, since they only make a spec-c sedan. JDM STi takeoffs can come from either though.

i'd also look for the p/n stickers that come on the struts, to verify that they are in fact what the seller claims that they are.