No, everything fits exactly, it's the same standard. I previously had a "Junghanns" and it fitted

Great, many thanks for the helpful answers. Dieter

As far as the flush and drain pipes are concerned, no difference, of course it will be difficult to reuse the same ones but new ones will have to be bought. The 12 mm threaded rods that support the toilet if you currently have a standard toilet will have to be longer. It's not a big job but if you are not in the trade it's not so obvious. Have a good evening
Loris