Car appreciation... the aesthetics, the engineering, etc

Doesn't all the Golf stuff just bolt up? I'd assumed it was that platform, is that a mistake?

Not really. There is some cross over but not as much as you'd think.

Availability is easier in the US as the 5C/A5 Beetle shares more many more parts with the Jetta (Bora) and Jettas sell very well in the US. I had one BITD and loved it.

For the more recent models, VW only sold about 30k cars Beetles per year in the US with the same sales numbers in Europe. Jetta numbers for Europe average closer to 15k. So the size of the aftermarket is pretty small in the grand scheme of things. (numbers from Calessalesbase)

The VW Vortex site, which should have a lot of the interchangeability info is too US focused and the UK forums are pretty dead. So there may be more options, but I am struggling to find the right information.

Thanks @mcmyk for the link. I have been using this web site as the diagrams are really useful.

https://vwsupply.co.uk/car-parts/9