XGworks is a sequencer, roughly comparable to Cakewalk, but with an XG editor, a dedicated drum window, an Auto arranger and a style creator. To create different sounds you use the XG editor to send sysex to the keyboard. You are not aware of the sysex unless you need to send special sysex that the XG editor doesn't recognise - i.e. keyboard specific. (I would add that I think this is the best XG editor around). It would work just fine on a PSR550, particularly as I have just done the instrument definitions for that keyboard. With the 550 and 740 you can use all the effects. With the 2000 you can use almost all but there is a limitation due to internal tables which cannot be changed. The 740 and 2000 have five DSPs, four are insert and one is Variation/insert.
You can use all of them in spite of what the manual says.

The style creator works by opening a style block after you have inserted the chords in the right place. You then select a style from the internal styles. You can also load external styles into the style file as long as they are in the right format.

XGworks stores the chord symbols in XF format which is Yamaha sysex so standard midi files won't display.

XGworks supports 2000 and XP in its current version but if you have anearlier version you have to download a patch.

Bryan