I've researched this issue for myself only quite recently. So the differences between the Stingray and the Sterling are still very fresh in my mind.
In addition to the difference in the preamp voicings, and the different pickup materials (alnico vs. ceramic), the pickups in each of these two models are wired differently from one another - the Stingray pickups wired in
parallel; the Sterling pickups wired in
series.
Anyone with actual experience in how these two configurations
sound will immediately recognize that each instrument naturally excels in discrete and distinct musical
applications. The clean, punchy tone of the Stingray is really ideal for any kind of funk or pop (think of Paul Denman's tone in the Sade band), whereas the somewhat thicker, more compressed, more aggressive growl of the Sterling is really perfect for rock - especially modern rock.
That's my take on it, at any rate...
MM