When it comes to general questions concerning types of equipment and their application, name brands such as Juwel Rio are not important. What you want to focus on is equipment type and their associated names, in this case a common rectangular aquarium and a simple common internal filter from what what I see on the Juwel Rio homepage.
In this case you can use any type filter you want (internal, canister, HOB, sump, exc) and can either replace or augment that internal filter (one of the most inexpensive entry level type). If you do decide to buy a different filter recommend an extrnal type as a replacement to save room inside the tank and and better looks.
I do not recommend any modifications to any designed filter by removing or add a part unless you are so familiar with the equipment that the need to ask why is not really necessary. If you have doubts about a DIY modification, its best not to do it without expecting some problems that could be costly
From what I see on the Juwell homepage the tanks and stands look pretty attractive, congratulations!
