Ok, I just looked on ford part outlet website - new would be ~$446 plus shipping. How about $220? I have no idea whether it's high or low.
As for eibach springs - I don't know an answer to your question but I read somewhere on this site a while back that your struts need to match your springs. Personally, I loved my BAT kit and it just worked out in a way that I couldn't take it off my old tour before trading it in. But it was pricey - with labor it cost me $800+ (but again, it was a sweet ride)