MZ towers are compatible with a 5 series. MZ system is universal to all older Celette benches. Think they now sell MZ+. IDK how far backwards compatible it is. If you are planning on getting one call Celette and they will answer any questions you have.
Have you ever used a Celette before? Or have experience with any frame/unibody system? Commercial or private use? Just curious. I will say that short of doing a major rust repair it's really overkill for a DIY'er. But if that's what you want more power to you. And remember just because you are using one, it's not magic, you got to set it up correctly and if you have to pull something you need to understand what's going on, and how to pull it out correctly. Just saying that if you are new to this.
Here is a link to the current catalog. Some good info in there.
https://www.celette.com/wp-content/uploads/2019/05/general-catalogue_compressed.pdf