Re: Prestige model difference
Are you sure you have the model numbers right? I have both an S1520 and an S2540. Neither is still in production. There are a number of differences: bubinga top on the 1520; middle single coil on the 2540 (1520 has only two hummers); gold hardware on the 2540; Wizard II neck on the 2540... Similarities: both were Japanese Prestige models, both had Lo-Pro Edge trem, QM pickups, mahogany bodies, and S body style. And both are fantastic instruments.
I think the last (updated) version of the S1520 lineage was the S1625 (last made in 2004?), which had the ZR tremelo with the D-tuner. The closest current model is the S2075 (H-S-H, burled top, ZR trem...), but that is a bit different from either of the other two.