There are several different things here. 

Toon! is a post-render effect that filters your raytraced render to look traditional cell animation.

Toon!Pro is an after-market plug-in available from Digital Carvers' Guild (who also developed Toon! originally that was acquired by Eovia and incorporated into Carrara).  Toon!Pro has much greater flexibility and control over how it creates cartoon-like images.

Non Photo-reallistic Renderer (NPR) is a different render engine included in Carrara.  It can create images that do not look photo-real -- they're rendered with "brush strokes" and "sketch" lines and such.

Unless I'm mistaken, Eovia acquired the code for Toon! from DCG (much like the code for Anything Glows, which is now incorporated into Carrara).  Toon!Pro is still a property of DCG.  As far as I know, the NPR was created for Carrara 4 and was not acquired from any other company.  So, if you're looking to make suggestions for the NPR, you should contact the friendly folks at DAZ (who bought Eovia).  If you're looking to make suggestions for Toon!Pro, you should contact Eric Winemiller at Digital Carvers' Guild. 

Hope that's helpful!

 - Dex