Hello SelArom, Eric Tangedahl,
Let me just add my input to the conversation.
For the development of complex data driven pages I would recommend that when you wrap this functionality into user controls or custom controls. In this way your controls can be uploaded to the CMS and used in the Page Editor (as Josh suggested). If you develop your controls as custom controls you will be able to use them across different Sitefinity projects. Another advantage of this would be that if you add pages as external to the CMS you can not do anything with them except for view or delete them, whereas adding the functionality to controls will allow you to take full advantage of the Sitefinity API.
I hope that this adds a little bit more to Josh's answer.
the Telerik team