Yamaha does not make a module of PSR sounds or styles. They have the QY products, but these feature only XG sounds and different pattern tracks. They now offer their Motif in a dance oriented box and the Motif does offer a few of the "sweet" voices such as flute and trumpet, but I wouldn't think most arranger musicians would run out and spend the $1600.00 or so dollars for the desk top Motif just to get a few extra sounds.
I wish Yamaha would make a module like Generalmusic has the WK2aranger and Solton has the X4. The industry has never done very well with module sales here in the US as compared to keyboards when it comes to arranger keyboards, and this is a big reason why you don't see to many. I've had many conversations with Yamaha and Roland product developers on this topic.
George Kaye
Kaye's Music Scene