It will be super tough to find them now. I bought mine 8 years ago. I did some looking around and they are not very readily available as I thought I had issues with my springs. I think that I do but it isn't bad enough for me to replace them.
I don't know where to steer you but you could start off calling the guys at memoryfab, they didn't have a line on them but knew some other performance sources that might be able to get them....
www.memoryfab.com.
At this point if I were you I'd skip spending the cash on the lowering springs unless your going to be married to this car for a heck of a long time and just work with memoryfab guys to find a set of KYB SR Specials struts & shocks. They will dramatically transform the way the car handles. Combine that with some 18 or 19" rims and you'll get your car to handle very nice.