How to transfer a site between cms?

Question

CMS

Hello!
Tell me how realistic and laborious it is to transfer the site between cms?
There is an online store on self-written cms company megagroup. I plan to migrate to magento. The company does not provide source code for the site. In the original cms, the first thing to do is to keep the ability to import via csv files. It is also necessary to completely copy the design of the site.

Answer 1

1. Current CMS - fully documented (including block diagrams, etc.!).
2. Compile TOR for the new CMS.
3. According to the TOR and current documentation - plan the transfer.
4. Transfer.

Answer 2

Really. In terms of costs, if there is x2 from scratch, then do not be surprised.