coil-overs

so i was looking on ebay and found these coil overs and since I dont know anything about anything,could someone tell me if these would be a bad purchase or not.Also if anyone has bought these then tell me if they are good or bad thanks.

here is the link

http://cgi.ebay.com/ebaymotors/90-00-MAZDA-MIATA-MX-5-COILOVER-SPRINGS-2YR-91-92-93-97_W0QQitemZ7987477088QQcategoryZ33582QQrdZ1QQcmdZ ViewItem

ya thats a good deal for the springs and adjusters but be carefull how low you drop that thing I got a complete set of TOKICO struts and springs off ebay for 350$ now it rides real real stiff almost to stiff and droped it an inch but with the new stiffer springs and sway bars it corners way better than before. another thing is if yer gonna do all this yer self make yer yer on level ground when setting up your ride heights as is it real easy to get one to high or to low
I measure at where the a arms connect to the frame hope this helps :)