Firstly the 300tdi filter assembly is too small for a 3.2TD and even marginal on the tdi. Automotive filters are often on the small side due to space considerations. Off-Highway filters are not which is why the sizes you are getting are larger, plus they are optimising around WOT rather than typical driving.
The powercore is the most compact filter available. However I would only use one if absolutely necessary as they have a higher pressure drop than a conventional filter with the same surface (filter) area.
MANN+HUMMEL had a similar product called the compact plus, however AFAIK they have discontinued development of new models.
Instead they are going for a "variopleat" system for applications where the filter needs to be as small as possible. These systems look like they perform better than the powercore. However there are only a few models available at present last I heard.
https://www.aulro.com/afvb/images/im...016/10/383.jpg
https://blog.mann-hummel.com/en/wp-c...Featured-1.png

