Sonar Studio and Sonar Producer are quite a bit different from MC and SHS. they are the "professional" versions of the software. the softsynth and FX limits are not there (technically they are just very, very high), the track limits are gone (again - very, very high), the GUI is very different but much more powerful and functional. there are many user functions in both programs not available in the lower softwares like Audiosnap (quantization for audio tracks), v-vocal (pitch correction), and many other features.

the differences between producer and studio are only the amount of toys you get with each (AFAIR). producer has many more FX and softsynths.