I've bought use suspension before. I got some used H&R coilovers for my S4. I ran them for over 40k...then I sold the car. You just won't have a warranty on them. What is the condition on them? I bought my B14's off a friend of mine. He had them on for 15k before he took them off. If they are still clean then they'll be worth a look. ~700usd seems like a good deal for some B14's.