To me the most relevant comparison is to the Mk1 Mini Countryman;

Puma is 4186mm long - 89 longer than MC (79mm longer than the current-gen Fabia by the way)

Puma is 1537mm tall - 24 lower than MC

Obviously there are more considerations that go into assessing the suitability of the Puma as a Rally2 car. But I was surprised to find out it’s lower than a Countryman so maybe it’s not so farfetched an idea?