I also had the SDS-9 back in 1985, and a Peavey keyboard amp, and dug it for what it was. Ultimately, the kit's not going to be worth a lot, I wouldn't even venture a guess. It's safe to say that the amp and cymbals will be worth more than the drums. But collectors and aficionados hang out at www.vdrums.com
, it couldn't hurt to ask over there.