I tried to Yahoo search, google search, and Froogle search "Otto Racing Springs" and all I got was the Pro Car Parts link and references to coilover spring kits. You are right about the Cruiser springs not being there anymore.
http://www.procarparts.com/store-subcat.asp?id=57
Note the last line of the third paragraph. It states that the "Otto" springs are imprinted with "Gold-Line". They must be the same thing.
Good find, by the way. It can be good to know who the real makers are. So many items are re-labled or re-branded.
Edit Added: Just found this "for 2000 and up"
http://www.procarparts.com/store-lis...cat=6&sub =49