I got my PSR SX900 last night and is awesome sounding!!!!
For your information, the PSR SX900 comes with 4 pre-loaded expansion packs, Africa, Europa, Middle Easter and Latin America ( a mixture of the Mariachi and Cumbia latina, neither complete, only partial, my guess, is that they made an evaluation and sort those like that), well, I made a especial SUPER PACK for installation using the new Yamaha Expansion Manager, and I could not believe my eyes, I put 19 expansion packs complete all with the exception of the Jazz/Swing Audio styles and still have room for 2 or 3 packs, depending on the size.
So far everything I have seen, I love it.
Now, a question that I have seen, you can download those pre-loaded packs plus others in this link, so, you can re-load them with others you may want to install besides.
https://europe.yamaha.com/en/products/musical_instruments/keyboards/arranger_workstations/psr-sx900/vse.htmlI will experiment more and let you know.
My 2 Cents
Having FUN
Manuel Dorantes