Understanding Crystal Reports Options

I know what Crystal Reports is from a report writing standpoint. I'm a little confused as to how the following products relate to crystal reports 2013.

1. Report Application Server - What is the difference between this and Crystal Reports Server
2. Restful Services - Are these part of another product. I know what a Rest service is, however are these part of RAS or Crystal Reports Server or something?

If our company was looking to write something similar to Crystal Reports Server in .NET, only on a smaller scale, is this doable? Would we build upon RAS or Restful services or would we have to completely write something from scratch

Thanks in advance