If the S-930 speakers sound good, and you like the way they sound, get em.
$39 is the price of a carton of cigarettes!
I have 2 pair of SP-2000s. I really love the SP-2000 sound, so much so, I bought a second NOS pair, for the closet, for a later day. Stene once mentioned that SP-2000s were Sansui's biggest selling speakers. The pair I am using sound as good as new, don't know why, they just shouldn't sound that good being so old. They sound simply wonderful. But that is the sound I like, the sound I grew up on, 'that Sansui speaker type sound'. Do a quick 'search' in AK for SP-2000s and read the threads.
I'd go for the SP-2000s if they work. Alnico magnets. Of course, ya gotta make sure all the speakers work, and there is a bunch of speakers. And...you may need to recap the crossovers, but that's not hard, but it may have to be done. 1970 is awhile back.
Try em both and take the best sounding to you. $35 +/- is cheap.
If you 'like the sound of the S-930s better' and the cabinets are in better shape, I'd go for the S-930s.
'Speaker sound enjoyment' is in the ears of the listener!
And...we all know Sansui made the best speakers in the world!!